diff --git a/app/Config/Events.php b/app/Config/Events.php
index 946285b89519..f360d558db45 100644
--- a/app/Config/Events.php
+++ b/app/Config/Events.php
@@ -25,7 +25,7 @@
 
 Events::on('pre_system', static function (): void {
     if (ENVIRONMENT !== 'testing') {
-        if (ini_get('zlib.output_compression')) {
+        if (! in_array(strtolower((string) ini_get('zlib.output_compression')), ['', '0', 'off'], true)) {
             throw FrameworkException::forEnabledZlibOutputCompression();
         }
 
diff --git a/user_guide_src/source/changelogs/v4.7.3.rst b/user_guide_src/source/changelogs/v4.7.3.rst
index b0eb65e687ab..6625c7ac7e5a 100644
--- a/user_guide_src/source/changelogs/v4.7.3.rst
+++ b/user_guide_src/source/changelogs/v4.7.3.rst
@@ -45,6 +45,7 @@ Bugs Fixed
 - **Database:** Fixed a bug where ``BaseConnection::listTables()`` could return a sparse array when using cached table names after a table was dropped.
 - **Database:** Fixed a bug where the PostgreSQL driver's ``increment()`` and ``decrement()`` methods were not working for numeric columns.
 - **Database:** Fixed a bug where the SQLSRV driver's decrement method was adding instead of subtracting the decrement value when ``$castTextToInt`` was false.
+- **Config:** Fixed a bug where the app starter's ``zlib.output_compression`` guard rejected the valid disabled value ``Off``.
 - **Entity:** Fixed a bug where ``Entity::normalizeValue()`` did not handle ``UnitEnum`` before checking for ``toArray()``, causing enums implementing ``toArray()`` to be incorrectly normalized as generic objects instead of enums.
 - **Kint:** Fixed a bug where stale Content Security Policy nonces were reused in worker mode, causing browser CSP violations for Debug Toolbar assets.
 - **Language:** Fixed a bug where ``Language::getLine()`` returned the literal dot-notation key instead of the nested array value when the requested key resolved to an intermediate array three or more levels deep.