diff --git a/docs/api.md b/docs/api.md
index 6ef4ac4b..4781381f 100644
--- a/docs/api.md
+++ b/docs/api.md
@@ -120,7 +120,7 @@ what gets sent over the wire.*
 >>> response = client.send(request)
 ```
 
-* `def __init__(method, url, [params], [headers], [cookies], [content], [data], [files], [json], [stream])`
+* `def __init__(method, url, [params], [headers], [cookies], [content], [data], [files], [json], [json_serializer], [json_deserializer], [stream])`
 * `.method` - **str**
 * `.url` - **URL**
 * `.content` - **byte**, **byte iterator**, or **byte async iterator**
diff --git a/docs/quickstart.md b/docs/quickstart.md
index 7cb3929c..518e4249 100644
--- a/docs/quickstart.md
+++ b/docs/quickstart.md
@@ -249,6 +249,17 @@ For more complicated data structures you'll often want to use JSON encoding inst
 }
 ```
 
+The JSON serializer and deserializer can be customized per request or per client.
+The serializer must accept the object passed as `json=...` and return either
+`str` or `bytes`. This allows serializers such as `orjson.dumps` to be used
+directly.
+
+```pycon
+>>> import orjson
+>>> with httpx.Client(json_serializer=orjson.dumps, json_deserializer=orjson.loads) as client:
+...     r = client.post("https://httpbin.org/post", json=data)
+```
+
 ## Sending Binary Request Data
 
 For other encodings, you should use the `content=...` parameter, passing
diff --git a/src/httpx2/httpx2/_api.py b/src/httpx2/httpx2/_api.py
index 95810605..09b823e7 100644
--- a/src/httpx2/httpx2/_api.py
+++ b/src/httpx2/httpx2/_api.py
@@ -10,6 +10,8 @@
     AuthTypes,
     CookieTypes,
     HeaderTypes,
+    JsonDeserializer,
+    JsonSerializer,
     ProxyTypes,
     QueryParamTypes,
     RequestContent,
@@ -45,6 +47,8 @@ def request(
     data: RequestData | None = None,
     files: RequestFiles | None = None,
     json: typing.Any | None = None,
+    json_serializer: JsonSerializer | None = None,
+    json_deserializer: JsonDeserializer | None = None,
     headers: HeaderTypes | None = None,
     cookies: CookieTypes | None = None,
     auth: AuthTypes | None = None,
@@ -105,6 +109,7 @@ def request(
         verify=verify,
         timeout=timeout,
         trust_env=trust_env,
+        json_deserializer=json_deserializer,
     ) as client:
         return client.request(
             method=method,
@@ -113,6 +118,8 @@ def request(
             data=data,
             files=files,
             json=json,
+            json_serializer=json_serializer,
+            json_deserializer=json_deserializer,
             params=params,
             headers=headers,
             auth=auth,
@@ -130,6 +137,8 @@ def stream(
     data: RequestData | None = None,
     files: RequestFiles | None = None,
     json: typing.Any | None = None,
+    json_serializer: JsonSerializer | None = None,
+    json_deserializer: JsonDeserializer | None = None,
     headers: HeaderTypes | None = None,
     cookies: CookieTypes | None = None,
     auth: AuthTypes | None = None,
@@ -155,6 +164,7 @@ def stream(
         verify=verify,
         timeout=timeout,
         trust_env=trust_env,
+        json_deserializer=json_deserializer,
     ) as client:
         with client.stream(
             method=method,
@@ -163,6 +173,8 @@ def stream(
             data=data,
             files=files,
             json=json,
+            json_serializer=json_serializer,
+            json_deserializer=json_deserializer,
             params=params,
             headers=headers,
             auth=auth,
@@ -182,6 +194,7 @@ def get(
     follow_redirects: bool = False,
     verify: ssl.SSLContext | str | bool = True,
     timeout: TimeoutTypes = DEFAULT_TIMEOUT_CONFIG,
+    json_deserializer: JsonDeserializer | None = None,
     trust_env: bool = True,
 ) -> Response:
     """
@@ -203,6 +216,7 @@ def get(
         follow_redirects=follow_redirects,
         verify=verify,
         timeout=timeout,
+        json_deserializer=json_deserializer,
         trust_env=trust_env,
     )
 
@@ -218,6 +232,7 @@ def options(
     follow_redirects: bool = False,
     verify: ssl.SSLContext | str | bool = True,
     timeout: TimeoutTypes = DEFAULT_TIMEOUT_CONFIG,
+    json_deserializer: JsonDeserializer | None = None,
     trust_env: bool = True,
 ) -> Response:
     """
@@ -239,6 +254,7 @@ def options(
         follow_redirects=follow_redirects,
         verify=verify,
         timeout=timeout,
+        json_deserializer=json_deserializer,
         trust_env=trust_env,
     )
 
@@ -254,6 +270,7 @@ def head(
     follow_redirects: bool = False,
     verify: ssl.SSLContext | str | bool = True,
     timeout: TimeoutTypes = DEFAULT_TIMEOUT_CONFIG,
+    json_deserializer: JsonDeserializer | None = None,
     trust_env: bool = True,
 ) -> Response:
     """
@@ -275,6 +292,7 @@ def head(
         follow_redirects=follow_redirects,
         verify=verify,
         timeout=timeout,
+        json_deserializer=json_deserializer,
         trust_env=trust_env,
     )
 
@@ -286,6 +304,7 @@ def post(
     data: RequestData | None = None,
     files: RequestFiles | None = None,
     json: typing.Any | None = None,
+    json_serializer: JsonSerializer | None = None,
     params: QueryParamTypes | None = None,
     headers: HeaderTypes | None = None,
     cookies: CookieTypes | None = None,
@@ -294,6 +313,7 @@ def post(
     follow_redirects: bool = False,
     verify: ssl.SSLContext | str | bool = True,
     timeout: TimeoutTypes = DEFAULT_TIMEOUT_CONFIG,
+    json_deserializer: JsonDeserializer | None = None,
     trust_env: bool = True,
 ) -> Response:
     """
@@ -308,6 +328,7 @@ def post(
         data=data,
         files=files,
         json=json,
+        json_serializer=json_serializer,
         params=params,
         headers=headers,
         cookies=cookies,
@@ -316,6 +337,7 @@ def post(
         follow_redirects=follow_redirects,
         verify=verify,
         timeout=timeout,
+        json_deserializer=json_deserializer,
         trust_env=trust_env,
     )
 
@@ -327,6 +349,7 @@ def put(
     data: RequestData | None = None,
     files: RequestFiles | None = None,
     json: typing.Any | None = None,
+    json_serializer: JsonSerializer | None = None,
     params: QueryParamTypes | None = None,
     headers: HeaderTypes | None = None,
     cookies: CookieTypes | None = None,
@@ -335,6 +358,7 @@ def put(
     follow_redirects: bool = False,
     verify: ssl.SSLContext | str | bool = True,
     timeout: TimeoutTypes = DEFAULT_TIMEOUT_CONFIG,
+    json_deserializer: JsonDeserializer | None = None,
     trust_env: bool = True,
 ) -> Response:
     """
@@ -349,6 +373,7 @@ def put(
         data=data,
         files=files,
         json=json,
+        json_serializer=json_serializer,
         params=params,
         headers=headers,
         cookies=cookies,
@@ -357,6 +382,7 @@ def put(
         follow_redirects=follow_redirects,
         verify=verify,
         timeout=timeout,
+        json_deserializer=json_deserializer,
         trust_env=trust_env,
     )
 
@@ -368,6 +394,7 @@ def patch(
     data: RequestData | None = None,
     files: RequestFiles | None = None,
     json: typing.Any | None = None,
+    json_serializer: JsonSerializer | None = None,
     params: QueryParamTypes | None = None,
     headers: HeaderTypes | None = None,
     cookies: CookieTypes | None = None,
@@ -376,6 +403,7 @@ def patch(
     follow_redirects: bool = False,
     verify: ssl.SSLContext | str | bool = True,
     timeout: TimeoutTypes = DEFAULT_TIMEOUT_CONFIG,
+    json_deserializer: JsonDeserializer | None = None,
     trust_env: bool = True,
 ) -> Response:
     """
@@ -390,6 +418,7 @@ def patch(
         data=data,
         files=files,
         json=json,
+        json_serializer=json_serializer,
         params=params,
         headers=headers,
         cookies=cookies,
@@ -398,6 +427,7 @@ def patch(
         follow_redirects=follow_redirects,
         verify=verify,
         timeout=timeout,
+        json_deserializer=json_deserializer,
         trust_env=trust_env,
     )
 
@@ -412,6 +442,7 @@ def delete(
     proxy: ProxyTypes | None = None,
     follow_redirects: bool = False,
     timeout: TimeoutTypes = DEFAULT_TIMEOUT_CONFIG,
+    json_deserializer: JsonDeserializer | None = None,
     verify: ssl.SSLContext | str | bool = True,
     trust_env: bool = True,
 ) -> Response:
@@ -434,5 +465,6 @@ def delete(
         follow_redirects=follow_redirects,
         verify=verify,
         timeout=timeout,
+        json_deserializer=json_deserializer,
         trust_env=trust_env,
     )
diff --git a/src/httpx2/httpx2/_client.py b/src/httpx2/httpx2/_client.py
index 3c950679..5b0e28c7 100644
--- a/src/httpx2/httpx2/_client.py
+++ b/src/httpx2/httpx2/_client.py
@@ -36,6 +36,8 @@
     CertTypes,
     CookieTypes,
     HeaderTypes,
+    JsonDeserializer,
+    JsonSerializer,
     ProxyTypes,
     QueryParamTypes,
     RequestContent,
@@ -190,6 +192,8 @@ def __init__(
         base_url: URL | str = "",
         trust_env: bool = True,
         default_encoding: str | typing.Callable[[bytes], str] = "utf-8",
+        json_serializer: JsonSerializer | None = None,
+        json_deserializer: JsonDeserializer | None = None,
     ) -> None:
         event_hooks = {} if event_hooks is None else event_hooks
 
@@ -208,6 +212,8 @@ def __init__(
         }
         self._trust_env = trust_env
         self._default_encoding = default_encoding
+        self._json_serializer = json_serializer
+        self._json_deserializer = json_deserializer
         self._state = ClientState.UNOPENED
 
     @property
@@ -331,6 +337,8 @@ def build_request(
         data: RequestData | None = None,
         files: RequestFiles | None = None,
         json: typing.Any | None = None,
+        json_serializer: JsonSerializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         params: QueryParamTypes | None = None,
         headers: HeaderTypes | None = None,
         cookies: CookieTypes | None = None,
@@ -353,6 +361,8 @@ def build_request(
         cookies = self._merge_cookies(cookies)
         params = self._merge_queryparams(params)
         extensions = {} if extensions is None else extensions
+        if not isinstance(json_deserializer, UseClientDefault):
+            extensions = dict(**extensions, json_deserializer=json_deserializer)
         if "timeout" not in extensions:
             timeout = self.timeout if isinstance(timeout, UseClientDefault) else Timeout(timeout)
             extensions = dict(**extensions, timeout=timeout.as_dict())
@@ -363,6 +373,7 @@ def build_request(
             data=data,
             files=files,
             json=json,
+            json_serializer=self._json_serializer if isinstance(json_serializer, UseClientDefault) else json_serializer,
             params=params,
             headers=headers,
             cookies=cookies,
@@ -629,6 +640,8 @@ def __init__(
         base_url: URL | str = "",
         transport: BaseTransport | None = None,
         default_encoding: str | typing.Callable[[bytes], str] = "utf-8",
+        json_serializer: JsonSerializer | None = None,
+        json_deserializer: JsonDeserializer | None = None,
     ) -> None:
         super().__init__(
             auth=auth,
@@ -642,6 +655,8 @@ def __init__(
             base_url=base_url,
             trust_env=trust_env,
             default_encoding=default_encoding,
+            json_serializer=json_serializer,
+            json_deserializer=json_deserializer,
         )
 
         if http2:
@@ -746,6 +761,8 @@ def request(
         data: RequestData | None = None,
         files: RequestFiles | None = None,
         json: typing.Any | None = None,
+        json_serializer: JsonSerializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         params: QueryParamTypes | None = None,
         headers: HeaderTypes | None = None,
         cookies: CookieTypes | None = None,
@@ -785,6 +802,8 @@ def request(
             data=data,
             files=files,
             json=json,
+            json_serializer=json_serializer,
+            json_deserializer=json_deserializer,
             params=params,
             headers=headers,
             cookies=cookies,
@@ -803,6 +822,8 @@ def stream(
         data: RequestData | None = None,
         files: RequestFiles | None = None,
         json: typing.Any | None = None,
+        json_serializer: JsonSerializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         params: QueryParamTypes | None = None,
         headers: HeaderTypes | None = None,
         cookies: CookieTypes | None = None,
@@ -828,6 +849,8 @@ def stream(
             data=data,
             files=files,
             json=json,
+            json_serializer=json_serializer,
+            json_deserializer=json_deserializer,
             params=params,
             headers=headers,
             cookies=cookies,
@@ -980,6 +1003,7 @@ def _send_single_request(self, request: Request) -> Response:
         response.stream = BoundSyncStream(response.stream, response=response, start=start)
         self.cookies.extract_cookies(response)
         response.default_encoding = self._default_encoding
+        response._json_deserializer = request.extensions.get("json_deserializer", self._json_deserializer)
 
         logger.info(
             'HTTP Request: %s %s "%s %d %s"',
@@ -1002,6 +1026,7 @@ def get(
         auth: AuthTypes | UseClientDefault | None = USE_CLIENT_DEFAULT,
         follow_redirects: bool | UseClientDefault = USE_CLIENT_DEFAULT,
         timeout: TimeoutTypes | UseClientDefault = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         extensions: RequestExtensions | None = None,
     ) -> Response:
         """
@@ -1018,6 +1043,7 @@ def get(
             auth=auth,
             follow_redirects=follow_redirects,
             timeout=timeout,
+            json_deserializer=json_deserializer,
             extensions=extensions,
         )
 
@@ -1031,6 +1057,7 @@ def options(
         auth: AuthTypes | UseClientDefault = USE_CLIENT_DEFAULT,
         follow_redirects: bool | UseClientDefault = USE_CLIENT_DEFAULT,
         timeout: TimeoutTypes | UseClientDefault = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         extensions: RequestExtensions | None = None,
     ) -> Response:
         """
@@ -1047,6 +1074,7 @@ def options(
             auth=auth,
             follow_redirects=follow_redirects,
             timeout=timeout,
+            json_deserializer=json_deserializer,
             extensions=extensions,
         )
 
@@ -1060,6 +1088,7 @@ def head(
         auth: AuthTypes | UseClientDefault = USE_CLIENT_DEFAULT,
         follow_redirects: bool | UseClientDefault = USE_CLIENT_DEFAULT,
         timeout: TimeoutTypes | UseClientDefault = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         extensions: RequestExtensions | None = None,
     ) -> Response:
         """
@@ -1076,6 +1105,7 @@ def head(
             auth=auth,
             follow_redirects=follow_redirects,
             timeout=timeout,
+            json_deserializer=json_deserializer,
             extensions=extensions,
         )
 
@@ -1087,6 +1117,8 @@ def post(
         data: RequestData | None = None,
         files: RequestFiles | None = None,
         json: typing.Any | None = None,
+        json_serializer: JsonSerializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         params: QueryParamTypes | None = None,
         headers: HeaderTypes | None = None,
         cookies: CookieTypes | None = None,
@@ -1107,6 +1139,8 @@ def post(
             data=data,
             files=files,
             json=json,
+            json_serializer=json_serializer,
+            json_deserializer=json_deserializer,
             params=params,
             headers=headers,
             cookies=cookies,
@@ -1124,6 +1158,8 @@ def put(
         data: RequestData | None = None,
         files: RequestFiles | None = None,
         json: typing.Any | None = None,
+        json_serializer: JsonSerializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         params: QueryParamTypes | None = None,
         headers: HeaderTypes | None = None,
         cookies: CookieTypes | None = None,
@@ -1144,6 +1180,8 @@ def put(
             data=data,
             files=files,
             json=json,
+            json_serializer=json_serializer,
+            json_deserializer=json_deserializer,
             params=params,
             headers=headers,
             cookies=cookies,
@@ -1161,6 +1199,8 @@ def patch(
         data: RequestData | None = None,
         files: RequestFiles | None = None,
         json: typing.Any | None = None,
+        json_serializer: JsonSerializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         params: QueryParamTypes | None = None,
         headers: HeaderTypes | None = None,
         cookies: CookieTypes | None = None,
@@ -1181,6 +1221,8 @@ def patch(
             data=data,
             files=files,
             json=json,
+            json_serializer=json_serializer,
+            json_deserializer=json_deserializer,
             params=params,
             headers=headers,
             cookies=cookies,
@@ -1200,6 +1242,7 @@ def delete(
         auth: AuthTypes | UseClientDefault = USE_CLIENT_DEFAULT,
         follow_redirects: bool | UseClientDefault = USE_CLIENT_DEFAULT,
         timeout: TimeoutTypes | UseClientDefault = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         extensions: RequestExtensions | None = None,
     ) -> Response:
         """
@@ -1216,6 +1259,7 @@ def delete(
             auth=auth,
             follow_redirects=follow_redirects,
             timeout=timeout,
+            json_deserializer=json_deserializer,
             extensions=extensions,
         )
 
@@ -1331,6 +1375,8 @@ def __init__(
         transport: AsyncBaseTransport | None = None,
         trust_env: bool = True,
         default_encoding: str | typing.Callable[[bytes], str] = "utf-8",
+        json_serializer: JsonSerializer | None = None,
+        json_deserializer: JsonDeserializer | None = None,
     ) -> None:
         super().__init__(
             auth=auth,
@@ -1344,6 +1390,8 @@ def __init__(
             base_url=base_url,
             trust_env=trust_env,
             default_encoding=default_encoding,
+            json_serializer=json_serializer,
+            json_deserializer=json_deserializer,
         )
 
         if http2:
@@ -1448,6 +1496,8 @@ async def request(
         data: RequestData | None = None,
         files: RequestFiles | None = None,
         json: typing.Any | None = None,
+        json_serializer: JsonSerializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         params: QueryParamTypes | None = None,
         headers: HeaderTypes | None = None,
         cookies: CookieTypes | None = None,
@@ -1488,6 +1538,8 @@ async def request(
             data=data,
             files=files,
             json=json,
+            json_serializer=json_serializer,
+            json_deserializer=json_deserializer,
             params=params,
             headers=headers,
             cookies=cookies,
@@ -1506,6 +1558,8 @@ async def stream(
         data: RequestData | None = None,
         files: RequestFiles | None = None,
         json: typing.Any | None = None,
+        json_serializer: JsonSerializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         params: QueryParamTypes | None = None,
         headers: HeaderTypes | None = None,
         cookies: CookieTypes | None = None,
@@ -1531,6 +1585,8 @@ async def stream(
             data=data,
             files=files,
             json=json,
+            json_serializer=json_serializer,
+            json_deserializer=json_deserializer,
             params=params,
             headers=headers,
             cookies=cookies,
@@ -1683,6 +1739,7 @@ async def _send_single_request(self, request: Request) -> Response:
         response.stream = BoundAsyncStream(response.stream, response=response, start=start)
         self.cookies.extract_cookies(response)
         response.default_encoding = self._default_encoding
+        response._json_deserializer = request.extensions.get("json_deserializer", self._json_deserializer)
 
         logger.info(
             'HTTP Request: %s %s "%s %d %s"',
@@ -1705,6 +1762,7 @@ async def get(
         auth: AuthTypes | UseClientDefault | None = USE_CLIENT_DEFAULT,
         follow_redirects: bool | UseClientDefault = USE_CLIENT_DEFAULT,
         timeout: TimeoutTypes | UseClientDefault = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         extensions: RequestExtensions | None = None,
     ) -> Response:
         """
@@ -1721,6 +1779,7 @@ async def get(
             auth=auth,
             follow_redirects=follow_redirects,
             timeout=timeout,
+            json_deserializer=json_deserializer,
             extensions=extensions,
         )
 
@@ -1734,6 +1793,7 @@ async def options(
         auth: AuthTypes | UseClientDefault = USE_CLIENT_DEFAULT,
         follow_redirects: bool | UseClientDefault = USE_CLIENT_DEFAULT,
         timeout: TimeoutTypes | UseClientDefault = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         extensions: RequestExtensions | None = None,
     ) -> Response:
         """
@@ -1750,6 +1810,7 @@ async def options(
             auth=auth,
             follow_redirects=follow_redirects,
             timeout=timeout,
+            json_deserializer=json_deserializer,
             extensions=extensions,
         )
 
@@ -1763,6 +1824,7 @@ async def head(
         auth: AuthTypes | UseClientDefault = USE_CLIENT_DEFAULT,
         follow_redirects: bool | UseClientDefault = USE_CLIENT_DEFAULT,
         timeout: TimeoutTypes | UseClientDefault = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         extensions: RequestExtensions | None = None,
     ) -> Response:
         """
@@ -1779,6 +1841,7 @@ async def head(
             auth=auth,
             follow_redirects=follow_redirects,
             timeout=timeout,
+            json_deserializer=json_deserializer,
             extensions=extensions,
         )
 
@@ -1790,6 +1853,8 @@ async def post(
         data: RequestData | None = None,
         files: RequestFiles | None = None,
         json: typing.Any | None = None,
+        json_serializer: JsonSerializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         params: QueryParamTypes | None = None,
         headers: HeaderTypes | None = None,
         cookies: CookieTypes | None = None,
@@ -1810,6 +1875,8 @@ async def post(
             data=data,
             files=files,
             json=json,
+            json_serializer=json_serializer,
+            json_deserializer=json_deserializer,
             params=params,
             headers=headers,
             cookies=cookies,
@@ -1827,6 +1894,8 @@ async def put(
         data: RequestData | None = None,
         files: RequestFiles | None = None,
         json: typing.Any | None = None,
+        json_serializer: JsonSerializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         params: QueryParamTypes | None = None,
         headers: HeaderTypes | None = None,
         cookies: CookieTypes | None = None,
@@ -1847,6 +1916,8 @@ async def put(
             data=data,
             files=files,
             json=json,
+            json_serializer=json_serializer,
+            json_deserializer=json_deserializer,
             params=params,
             headers=headers,
             cookies=cookies,
@@ -1864,6 +1935,8 @@ async def patch(
         data: RequestData | None = None,
         files: RequestFiles | None = None,
         json: typing.Any | None = None,
+        json_serializer: JsonSerializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         params: QueryParamTypes | None = None,
         headers: HeaderTypes | None = None,
         cookies: CookieTypes | None = None,
@@ -1884,6 +1957,8 @@ async def patch(
             data=data,
             files=files,
             json=json,
+            json_serializer=json_serializer,
+            json_deserializer=json_deserializer,
             params=params,
             headers=headers,
             cookies=cookies,
@@ -1903,6 +1978,7 @@ async def delete(
         auth: AuthTypes | UseClientDefault = USE_CLIENT_DEFAULT,
         follow_redirects: bool | UseClientDefault = USE_CLIENT_DEFAULT,
         timeout: TimeoutTypes | UseClientDefault = USE_CLIENT_DEFAULT,
+        json_deserializer: JsonDeserializer | UseClientDefault | None = USE_CLIENT_DEFAULT,
         extensions: RequestExtensions | None = None,
     ) -> Response:
         """
@@ -1919,6 +1995,7 @@ async def delete(
             auth=auth,
             follow_redirects=follow_redirects,
             timeout=timeout,
+            json_deserializer=json_deserializer,
             extensions=extensions,
         )
 
diff --git a/src/httpx2/httpx2/_content.py b/src/httpx2/httpx2/_content.py
index 71969ecc..9f2e06aa 100644
--- a/src/httpx2/httpx2/_content.py
+++ b/src/httpx2/httpx2/_content.py
@@ -17,6 +17,7 @@
 from ._multipart import MultipartStream
 from ._types import (
     AsyncByteStream,
+    JsonSerializer,
     RequestContent,
     RequestData,
     RequestFiles,
@@ -28,6 +29,10 @@
 __all__ = ["ByteStream"]
 
 
+def default_json_serializer(json: Any) -> str:
+    return json_dumps(json, ensure_ascii=False, separators=(",", ":"), allow_nan=False)
+
+
 class ByteStream(AsyncByteStream, SyncByteStream):
     def __init__(self, stream: bytes) -> None:
         self._stream = stream
@@ -173,8 +178,13 @@ def encode_html(html: str) -> tuple[dict[str, str], ByteStream]:
     return headers, ByteStream(body)
 
 
-def encode_json(json: Any) -> tuple[dict[str, str], ByteStream]:
-    body = json_dumps(json, ensure_ascii=False, separators=(",", ":"), allow_nan=False).encode("utf-8")
+def encode_json(json: Any, json_serializer: JsonSerializer | None = None) -> tuple[dict[str, str], ByteStream]:
+    dumps = default_json_serializer if json_serializer is None else json_serializer
+    body = dumps(json)
+    if isinstance(body, str):
+        body = body.encode("utf-8")
+    elif not isinstance(body, bytes):
+        raise TypeError(f"JSON serializer returned unsupported type {type(body)!r}; expected str or bytes")
     content_length = str(len(body))
     content_type = "application/json"
     headers = {"Content-Length": content_length, "Content-Type": content_type}
@@ -186,6 +196,7 @@ def encode_request(
     data: RequestData | None = None,
     files: RequestFiles | None = None,
     json: Any | None = None,
+    json_serializer: JsonSerializer | None = None,
     boundary: bytes | None = None,
 ) -> tuple[dict[str, str], SyncByteStream | AsyncByteStream]:
     """
@@ -211,7 +222,7 @@ def encode_request(
     elif data:
         return encode_urlencoded_data(data)
     elif json is not None:
-        return encode_json(json)
+        return encode_json(json, json_serializer=json_serializer)
 
     return {}, ByteStream(b"")
 
@@ -221,6 +232,7 @@ def encode_response(
     text: str | None = None,
     html: str | None = None,
     json: Any | None = None,
+    json_serializer: JsonSerializer | None = None,
 ) -> tuple[dict[str, str], SyncByteStream | AsyncByteStream]:
     """
     Handles encoding the given `content`, returning a two-tuple of
@@ -233,6 +245,6 @@ def encode_response(
     elif html is not None:
         return encode_html(html)
     elif json is not None:
-        return encode_json(json)
+        return encode_json(json, json_serializer=json_serializer)
 
     return {}, ByteStream(b"")
diff --git a/src/httpx2/httpx2/_models.py b/src/httpx2/httpx2/_models.py
index 02baa3eb..a94993de 100644
--- a/src/httpx2/httpx2/_models.py
+++ b/src/httpx2/httpx2/_models.py
@@ -36,6 +36,8 @@
     AsyncByteStream,
     CookieTypes,
     HeaderTypes,
+    JsonDeserializer,
+    JsonSerializer,
     QueryParamTypes,
     RequestContent,
     RequestData,
@@ -381,6 +383,7 @@ def __init__(
         data: RequestData | None = None,
         files: RequestFiles | None = None,
         json: typing.Any | None = None,
+        json_serializer: JsonSerializer | None = None,
         stream: SyncByteStream | AsyncByteStream | None = None,
         extensions: RequestExtensions | None = None,
     ) -> None:
@@ -399,6 +402,7 @@ def __init__(
                 data=data,
                 files=files,
                 json=json,
+                json_serializer=json_serializer,
                 boundary=get_multipart_boundary_from_content_type(
                     content_type=content_type.encode(self.headers.encoding) if content_type else None
                 ),
@@ -503,6 +507,8 @@ def __init__(
         text: str | None = None,
         html: str | None = None,
         json: typing.Any = None,
+        json_serializer: JsonSerializer | None = None,
+        json_deserializer: JsonDeserializer | None = None,
         stream: SyncByteStream | AsyncByteStream | None = None,
         request: Request | None = None,
         extensions: ResponseExtensions | None = None,
@@ -513,6 +519,7 @@ def __init__(
         self.headers = Headers(headers)
 
         self._request: Request | None = request
+        self._json_deserializer = json_deserializer
 
         # When follow_redirects=False and a redirect is received,
         # the client will set `response.next_request`.
@@ -527,7 +534,7 @@ def __init__(
         self.default_encoding = default_encoding
 
         if stream is None:
-            headers, stream = encode_response(content, text, html, json)
+            headers, stream = encode_response(content, text, html, json, json_serializer=json_serializer)
             self._prepare(headers)
             self.stream = stream
             if isinstance(stream, ByteStream):
@@ -802,6 +809,10 @@ def raise_for_status(self) -> Response:
         raise HTTPStatusError(message, request=request, response=self)
 
     def json(self, **kwargs: typing.Any) -> typing.Any:
+        if self._json_deserializer is not None:
+            if kwargs:
+                raise TypeError("Response.json() keyword arguments are only supported with the default JSON decoder")
+            return self._json_deserializer(self.content)
         return jsonlib.loads(self.content, **kwargs)
 
     @property
diff --git a/src/httpx2/httpx2/_types.py b/src/httpx2/httpx2/_types.py
index 99a91d3b..ff0e85fb 100644
--- a/src/httpx2/httpx2/_types.py
+++ b/src/httpx2/httpx2/_types.py
@@ -70,6 +70,8 @@
 ResponseExtensions = Mapping[str, Any]
 
 RequestData = Mapping[str, Any]
+JsonSerializer = Callable[[Any], Union[str, bytes]]
+JsonDeserializer = Callable[[Union[bytes, str]], Any]
 
 FileContent = Union[IO[bytes], bytes, str]
 FileTypes = Union[
diff --git a/tests/httpx2/client/test_async_client.py b/tests/httpx2/client/test_async_client.py
index ccc73813..18727648 100644
--- a/tests/httpx2/client/test_async_client.py
+++ b/tests/httpx2/client/test_async_client.py
@@ -67,6 +67,36 @@ async def test_post_json(server):
     assert response.status_code == 200
 
 
+@pytest.mark.anyio
+async def test_async_client_json_serializer():
+    def echo_body(request: httpx2.Request) -> httpx2.Response:
+        return httpx2.Response(200, content=request.content)
+
+    def dumps(data: typing.Any) -> bytes:
+        assert data == {"text": "Hello, world!"}
+        return b'{"text":"custom!"}'
+
+    async with httpx2.AsyncClient(transport=httpx2.MockTransport(echo_body), json_serializer=dumps) as client:
+        response = await client.post("https://example.org", json={"text": "Hello, world!"})
+
+    assert response.content == b'{"text":"custom!"}'
+
+
+@pytest.mark.anyio
+async def test_async_client_json_deserializer():
+    def json_response(request: httpx2.Request) -> httpx2.Response:
+        return httpx2.Response(200, content=b'{"text":"Hello, world!"}')
+
+    def loads(content: bytes | str) -> typing.Any:
+        assert content == b'{"text":"Hello, world!"}'
+        return {"text": "custom!"}
+
+    async with httpx2.AsyncClient(transport=httpx2.MockTransport(json_response), json_deserializer=loads) as client:
+        response = await client.get("https://example.org")
+
+    assert response.json() == {"text": "custom!"}
+
+
 @pytest.mark.anyio
 async def test_stream_response(server):
     async with httpx2.AsyncClient() as client:
diff --git a/tests/httpx2/client/test_client.py b/tests/httpx2/client/test_client.py
index e39e17d7..2ec11288 100644
--- a/tests/httpx2/client/test_client.py
+++ b/tests/httpx2/client/test_client.py
@@ -89,6 +89,92 @@ def test_post_json(server):
     assert response.reason_phrase == "OK"
 
 
+def test_client_json_serializer():
+    def echo_body(request: httpx2.Request) -> httpx2.Response:
+        return httpx2.Response(200, content=request.content)
+
+    def dumps(data: typing.Any) -> bytes:
+        assert data == {"text": "Hello, world!"}
+        return b'{"text":"custom!"}'
+
+    with httpx2.Client(transport=httpx2.MockTransport(echo_body), json_serializer=dumps) as client:
+        response = client.post("https://example.org", json={"text": "Hello, world!"})
+
+    assert response.content == b'{"text":"custom!"}'
+
+
+def test_request_json_serializer_overrides_client_default():
+    def echo_body(request: httpx2.Request) -> httpx2.Response:
+        return httpx2.Response(200, content=request.content)
+
+    def client_dumps(data: typing.Any) -> bytes:
+        return b'{"source":"client"}'
+
+    def request_dumps(data: typing.Any) -> bytes:
+        return b'{"source":"request"}'
+
+    with httpx2.Client(transport=httpx2.MockTransport(echo_body), json_serializer=client_dumps) as client:
+        response = client.post("https://example.org", json={"text": "Hello, world!"}, json_serializer=request_dumps)
+
+    assert response.content == b'{"source":"request"}'
+
+
+def test_request_json_serializer_can_use_builtin_default():
+    def echo_body(request: httpx2.Request) -> httpx2.Response:
+        return httpx2.Response(200, content=request.content)
+
+    def client_dumps(data: typing.Any) -> bytes:
+        return b'{"source":"client"}'
+
+    with httpx2.Client(transport=httpx2.MockTransport(echo_body), json_serializer=client_dumps) as client:
+        response = client.post("https://example.org", json={"text": "Hello, world!"}, json_serializer=None)
+
+    assert response.content == b'{"text":"Hello, world!"}'
+
+
+def test_client_json_deserializer():
+    def json_response(request: httpx2.Request) -> httpx2.Response:
+        return httpx2.Response(200, content=b'{"text":"Hello, world!"}')
+
+    def loads(content: bytes | str) -> typing.Any:
+        assert content == b'{"text":"Hello, world!"}'
+        return {"text": "custom!"}
+
+    with httpx2.Client(transport=httpx2.MockTransport(json_response), json_deserializer=loads) as client:
+        response = client.get("https://example.org")
+
+    assert response.json() == {"text": "custom!"}
+
+
+def test_request_json_deserializer_overrides_client_default():
+    def json_response(request: httpx2.Request) -> httpx2.Response:
+        return httpx2.Response(200, content=b'{"text":"Hello, world!"}')
+
+    def client_loads(content: bytes | str) -> typing.Any:
+        return {"source": "client"}
+
+    def request_loads(content: bytes | str) -> typing.Any:
+        return {"source": "request"}
+
+    with httpx2.Client(transport=httpx2.MockTransport(json_response), json_deserializer=client_loads) as client:
+        response = client.get("https://example.org", json_deserializer=request_loads)
+
+    assert response.json() == {"source": "request"}
+
+
+def test_request_json_deserializer_can_use_builtin_default():
+    def json_response(request: httpx2.Request) -> httpx2.Response:
+        return httpx2.Response(200, content=b'{"text":"Hello, world!"}')
+
+    def client_loads(content: bytes | str) -> typing.Any:
+        return {"source": "client"}
+
+    with httpx2.Client(transport=httpx2.MockTransport(json_response), json_deserializer=client_loads) as client:
+        response = client.get("https://example.org", json_deserializer=None)
+
+    assert response.json() == {"text": "Hello, world!"}
+
+
 def test_stream_response(server):
     with httpx2.Client() as client:
         with client.stream("GET", server.url) as response:
diff --git a/tests/httpx2/test_content.py b/tests/httpx2/test_content.py
index 77a3b7f5..1b8483f4 100644
--- a/tests/httpx2/test_content.py
+++ b/tests/httpx2/test_content.py
@@ -180,6 +180,36 @@ async def test_json_content():
     assert async_content == b'{"Hello":"world!"}'
 
 
+@pytest.mark.anyio
+async def test_json_content_with_custom_serializer():
+    def dumps(data: typing.Any) -> bytes:
+        assert data == {"Hello": "world!"}
+        return b'{"Hello":"custom!"}'
+
+    request = httpx2.Request(method, url, json={"Hello": "world!"}, json_serializer=dumps)
+    assert isinstance(request.stream, typing.Iterable)
+    assert isinstance(request.stream, typing.AsyncIterable)
+
+    sync_content = b"".join(list(request.stream))
+    async_content = b"".join([part async for part in request.stream])
+
+    assert request.headers == {
+        "Host": "www.example.com",
+        "Content-Length": "19",
+        "Content-Type": "application/json",
+    }
+    assert sync_content == b'{"Hello":"custom!"}'
+    assert async_content == b'{"Hello":"custom!"}'
+
+
+def test_json_serializer_must_return_str_or_bytes():
+    def dumps(data: typing.Any) -> object:
+        return data
+
+    with pytest.raises(TypeError, match="JSON serializer returned unsupported type"):
+        httpx2.Request(method, url, json={"Hello": "world!"}, json_serializer=dumps)  # type: ignore[arg-type]
+
+
 @pytest.mark.anyio
 async def test_urlencoded_content():
     request = httpx2.Request(method, url, data={"Hello": "world!"})
@@ -502,6 +532,35 @@ def test_separators_for_compact_json():
     assert response.headers["Content-Type"] == "application/json"
 
 
+def test_response_json_with_custom_serializer():
+    def dumps(data: typing.Any) -> str:
+        assert data == {"Hello": "world!"}
+        return '{"Hello":"custom!"}'
+
+    response = httpx2.Response(200, json={"Hello": "world!"}, json_serializer=dumps)
+
+    assert response.content == b'{"Hello":"custom!"}'
+    assert response.headers["Content-Length"] == "19"
+    assert response.headers["Content-Type"] == "application/json"
+
+
+def test_response_json_with_custom_deserializer():
+    def loads(content: bytes | str) -> typing.Any:
+        assert content == b'{"Hello":"world!"}'
+        return {"Hello": "custom!"}
+
+    response = httpx2.Response(200, content=b'{"Hello":"world!"}', json_deserializer=loads)
+
+    assert response.json() == {"Hello": "custom!"}
+
+
+def test_custom_json_deserializer_rejects_loads_kwargs():
+    response = httpx2.Response(200, content=b'{"Hello":"world!"}', json_deserializer=lambda content: {})
+
+    with pytest.raises(TypeError, match="keyword arguments are only supported"):
+        response.json(parse_float=float)
+
+
 def test_allow_nan_false():
     data_with_nan = {"nombre": float("nan")}
     data_with_inf = {"nombre": float("inf")}