diff --git a/change/change-bun-workspace-tools.json b/change/change-bun-workspace-tools.json
new file mode 100644
index 000000000..7a3941168
--- /dev/null
+++ b/change/change-bun-workspace-tools.json
@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "type": "patch",
+      "comment": "Add bun as a supported workspace manager in workspace-tools, including manager detection and workspace fixture/test coverage.",
+      "packageName": "workspace-tools",
+      "email": "email not defined",
+      "dependentChangeType": "patch"
+    }
+  ]
+}
diff --git a/packages/workspace-tools/README.md b/packages/workspace-tools/README.md
index 55d215aef..f9eb6da4b 100644
--- a/packages/workspace-tools/README.md
+++ b/packages/workspace-tools/README.md
@@ -3,6 +3,7 @@
 A collection of utilities that are useful in a git-controlled monorepo managed by one of these tools:
 
 - lerna
+- bun workspaces
 - npm workspaces
 - pnpm workspaces
 - rush
@@ -20,7 +21,7 @@ Override the `maxBuffer` value for git processes, for example if the repo is ver
 
 ### PREFERRED_WORKSPACE_MANAGER
 
-Sometimes if multiple workspace/monorepo manager files are checked in, it's necessary to hint which manager is used: `npm`, `yarn`, `pnpm`, `rush`, or `lerna`. Some APIs also accept a `manager` parameter, which is now the preferred method when available.
+Sometimes if multiple workspace/monorepo manager files are checked in, it's necessary to hint which manager is used: `bun`, `npm`, `yarn`, `pnpm`, `rush`, or `lerna`. Some APIs also accept a `manager` parameter, which is now the preferred method when available.
 
 ### VERBOSE
 
diff --git a/packages/workspace-tools/etc/workspace-tools.api.md b/packages/workspace-tools/etc/workspace-tools.api.md
index dab612d8e..68a688795 100644
--- a/packages/workspace-tools/etc/workspace-tools.api.md
+++ b/packages/workspace-tools/etc/workspace-tools.api.md
@@ -696,7 +696,7 @@ export function stageAndCommit(patterns: string[], message: string, cwd: string,
 export type WorkspaceInfos = WorkspacePackageInfo[];
 
 // @public (undocumented)
-export type WorkspaceManager = "yarn" | "pnpm" | "rush" | "npm" | "lerna";
+export type WorkspaceManager = "yarn" | "pnpm" | "rush" | "npm" | "lerna" | "bun";
 
 // @public (undocumented)
 interface WorkspaceManagerAndRoot {
diff --git a/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/README.md b/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/README.md
new file mode 100644
index 000000000..7a1804142
--- /dev/null
+++ b/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/README.md
@@ -0,0 +1,5 @@
+This fixture is intended to match the other `monorepo-basic-*` fixtures (bun):
+
+- Workspaces: `["packages/*", "individual"]`
+- Same basic dependencies at root
+- `package-a` depends on `react` and `react-dom` (to introduce a `peerDependency`)
diff --git a/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/bun.lock b/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/bun.lock
new file mode 100644
index 000000000..e69de29bb
diff --git a/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/individual/package.json b/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/individual/package.json
new file mode 100644
index 000000000..ec1362d53
--- /dev/null
+++ b/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/individual/package.json
@@ -0,0 +1,5 @@
+{
+  "name": "individual",
+  "license": "MIT",
+  "version": "0.1.0"
+}
diff --git a/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/package.json b/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/package.json
new file mode 100644
index 000000000..8f9352fc9
--- /dev/null
+++ b/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/package.json
@@ -0,0 +1,17 @@
+{
+  "name": "monorepo-basic-bun",
+  "description": "Basic monorepo with bun (workspaces and deps should match other monorepo-basic-*)",
+  "license": "MIT",
+  "version": "0.1.0",
+  "private": true,
+  "devDependencies": {
+    "@types/node": "^20.0.0",
+    "typescript": "^4.0.0"
+  },
+  "workspaces": {
+    "packages": [
+      "packages/*",
+      "individual"
+    ]
+  }
+}
diff --git a/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/packages/package-a/package.json b/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/packages/package-a/package.json
new file mode 100644
index 000000000..1c3fb64f0
--- /dev/null
+++ b/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/packages/package-a/package.json
@@ -0,0 +1,9 @@
+{
+  "name": "package-a",
+  "license": "MIT",
+  "version": "0.1.0",
+  "dependencies": {
+    "react": "^19.0.0",
+    "react-dom": "^19.0.0"
+  }
+}
diff --git a/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/packages/package-b/package.json b/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/packages/package-b/package.json
new file mode 100644
index 000000000..8b6623a6e
--- /dev/null
+++ b/packages/workspace-tools/src/__fixtures__/monorepo-basic-bun/packages/package-b/package.json
@@ -0,0 +1,5 @@
+{
+  "name": "package-b",
+  "license": "MIT",
+  "version": "0.1.0"
+}
diff --git a/packages/workspace-tools/src/__tests__/setupFixture.ts b/packages/workspace-tools/src/__tests__/setupFixture.ts
index 0016aa4d4..5031b127a 100644
--- a/packages/workspace-tools/src/__tests__/setupFixture.ts
+++ b/packages/workspace-tools/src/__tests__/setupFixture.ts
@@ -16,6 +16,7 @@ type RealFixtureName =
   | "extra-yarn-1"
   | "extra-yarn-berry"
   | "monorepo-basic-npm"
+  | "monorepo-basic-bun"
   | "monorepo-basic-pnpm"
   | "monorepo-basic-yarn-1"
   | "monorepo-basic-yarn-berry"
diff --git a/packages/workspace-tools/src/__tests__/workspaces/getWorkspaceManagerAndRoot.test.ts b/packages/workspace-tools/src/__tests__/workspaces/getWorkspaceManagerAndRoot.test.ts
index d76af6ffd..7ac7192af 100644
--- a/packages/workspace-tools/src/__tests__/workspaces/getWorkspaceManagerAndRoot.test.ts
+++ b/packages/workspace-tools/src/__tests__/workspaces/getWorkspaceManagerAndRoot.test.ts
@@ -21,6 +21,7 @@ describe("getWorkspaceManagerAndRoot", () => {
     { desc: "yarn", manager: "yarn", fixtureName: "monorepo-basic-yarn-1" },
     { desc: "yarn berry", manager: "yarn", fixtureName: "monorepo-basic-yarn-berry" },
     { desc: "pnpm", manager: "pnpm", fixtureName: "monorepo-basic-pnpm" },
+    { desc: "bun", manager: "bun", fixtureName: "monorepo-basic-bun" },
     { desc: "rush", manager: "rush", fixtureName: "monorepo-rush-pnpm" },
     { desc: "npm", manager: "npm", fixtureName: "monorepo-basic-npm" },
     { desc: "lerna + npm", manager: "lerna", fixtureName: "monorepo-basic-lerna-npm" },
@@ -44,6 +45,17 @@ describe("getWorkspaceManagerAndRoot", () => {
     });
   });
 
+  it("detects bun workspace root with bun.lockb", () => {
+    const repoRoot = setupFixture("monorepo-basic-bun");
+    fs.rmSync(path.join(repoRoot, "bun.lock"));
+    fs.writeFileSync(path.join(repoRoot, "bun.lockb"), "");
+
+    expect(getWorkspaceManagerAndRoot(repoRoot)).toEqual({
+      root: repoRoot,
+      manager: "bun",
+    });
+  });
+
   it("handles nested monorepo", () => {
     // This fixture has a monorepo under the "monorepo" folder, not at the git root.
     const repoRoot = setupFixture("monorepo-nested", { git: true });
diff --git a/packages/workspace-tools/src/__tests__/workspaces/getWorkspaces.test.ts b/packages/workspace-tools/src/__tests__/workspaces/getWorkspaces.test.ts
index a93a37aae..e6ada4ba5 100644
--- a/packages/workspace-tools/src/__tests__/workspaces/getWorkspaces.test.ts
+++ b/packages/workspace-tools/src/__tests__/workspaces/getWorkspaces.test.ts
@@ -17,6 +17,7 @@ describe("getWorkspaceInfos", () => {
   }>([
     { manager: "yarn", desc: "yarn", fixtureName: "monorepo-basic-yarn-1" },
     { manager: "pnpm", desc: "pnpm", fixtureName: "monorepo-basic-pnpm" },
+    { manager: "bun", desc: "bun", fixtureName: "monorepo-basic-bun" },
     { manager: "rush", desc: "rush + pnpm", fixtureName: "monorepo-rush-pnpm" },
     { manager: "rush", desc: "rush + yarn", fixtureName: "monorepo-rush-yarn" },
     { manager: "npm", desc: "npm", fixtureName: "monorepo-basic-npm" },
diff --git a/packages/workspace-tools/src/types/WorkspaceManager.ts b/packages/workspace-tools/src/types/WorkspaceManager.ts
index ee41f0f17..fa299243a 100644
--- a/packages/workspace-tools/src/types/WorkspaceManager.ts
+++ b/packages/workspace-tools/src/types/WorkspaceManager.ts
@@ -1 +1 @@
-export type WorkspaceManager = "yarn" | "pnpm" | "rush" | "npm" | "lerna";
+export type WorkspaceManager = "yarn" | "pnpm" | "rush" | "npm" | "lerna" | "bun";
diff --git a/packages/workspace-tools/src/workspaces/implementations/bun.ts b/packages/workspace-tools/src/workspaces/implementations/bun.ts
new file mode 100644
index 000000000..216c6aa42
--- /dev/null
+++ b/packages/workspace-tools/src/workspaces/implementations/bun.ts
@@ -0,0 +1,9 @@
+import { getPackageJsonWorkspacePatterns } from "./getPackageJsonWorkspacePatterns.js";
+import type { WorkspaceUtilities } from "./WorkspaceUtilities.js";
+
+/**
+ * Bun uses the standard package.json "workspaces" field.
+ */
+export const bunUtilities: WorkspaceUtilities = {
+  getWorkspacePatterns: getPackageJsonWorkspacePatterns,
+};
diff --git a/packages/workspace-tools/src/workspaces/implementations/getWorkspaceManagerAndRoot.ts b/packages/workspace-tools/src/workspaces/implementations/getWorkspaceManagerAndRoot.ts
index bae8ae458..5c0731b8e 100644
--- a/packages/workspace-tools/src/workspaces/implementations/getWorkspaceManagerAndRoot.ts
+++ b/packages/workspace-tools/src/workspaces/implementations/getWorkspaceManagerAndRoot.ts
@@ -24,9 +24,15 @@ export const managerFiles = {
   rush: "rush.json",
   yarn: "yarn.lock",
   pnpm: "pnpm-workspace.yaml",
+  bun: ["bun.lock", "bun.lockb"],
   npm: "package-lock.json",
 } as const;
 
+function getManagerFileNames(manager: WorkspaceManager): string[] {
+  const fileOrFiles = managerFiles[manager];
+  return typeof fileOrFiles === "string" ? [fileOrFiles] : [...fileOrFiles];
+}
+
 /**
  * Get the preferred workspace/monorepo manager based on `process.env.PREFERRED_WORKSPACE_MANAGER`
  * (if valid).
@@ -57,7 +63,9 @@ export function getWorkspaceManagerAndRoot(
   }
 
   managerOverride ??= getPreferredWorkspaceManager();
-  const filesToSearch = managerOverride ? managerFiles[managerOverride] : Object.values(managerFiles);
+  const filesToSearch = managerOverride
+    ? getManagerFileNames(managerOverride)
+    : Object.values(managerFiles).flatMap((files) => (Array.isArray(files) ? files : [files]));
   const managerFile = searchUp(filesToSearch, cwd);
 
   if (managerFile) {
@@ -65,7 +73,7 @@ export function getWorkspaceManagerAndRoot(
     cache.set(cwd, {
       manager:
         managerOverride ||
-        (Object.keys(managerFiles) as WorkspaceManager[]).find((name) => managerFiles[name] === managerFileName)!,
+        (Object.keys(managerFiles) as WorkspaceManager[]).find((name) => getManagerFileNames(name).includes(managerFileName))!,
       root: path.dirname(managerFile),
     });
   } else {
diff --git a/packages/workspace-tools/src/workspaces/implementations/getWorkspaceUtilities.ts b/packages/workspace-tools/src/workspaces/implementations/getWorkspaceUtilities.ts
index bfa6138b9..61815d081 100644
--- a/packages/workspace-tools/src/workspaces/implementations/getWorkspaceUtilities.ts
+++ b/packages/workspace-tools/src/workspaces/implementations/getWorkspaceUtilities.ts
@@ -8,6 +8,11 @@ const utils: Partial<Record<WorkspaceManager, WorkspaceUtilities>> = {};
  */
 export function getWorkspaceUtilities(manager: WorkspaceManager): WorkspaceUtilities {
   switch (manager) {
+    case "bun":
+      // eslint-disable-next-line @typescript-eslint/consistent-type-imports, @typescript-eslint/no-require-imports
+      utils.bun ??= (require("./bun") as typeof import("./bun")).bunUtilities;
+      break;
+
     case "npm":
       // eslint-disable-next-line @typescript-eslint/consistent-type-imports, @typescript-eslint/no-require-imports
       utils.npm ??= (require("./npm") as typeof import("./npm")).npmUtilities;