diff --git a/ChangeLog-10.5.md b/ChangeLog-10.5.md
index 05851fd05f..81540aabd8 100644
--- a/ChangeLog-10.5.md
+++ b/ChangeLog-10.5.md
@@ -4,6 +4,10 @@ All notable changes of the PHPUnit 10.5 release series are documented in this fi
 
 ## [10.5.35] - 2024-MM-DD
 
+### Changed
+
+* [#5956](https://github.com/sebastianbergmann/phpunit/issues/5956): Deprecation of the `E_STRICT` constant in PHP 8.4
+
 ### Fixed
 
 * [#5950](https://github.com/sebastianbergmann/phpunit/pull/5950): TestDox text should not be `trim()`med when it contains `$` character
diff --git a/src/Runner/ErrorHandler.php b/src/Runner/ErrorHandler.php
index 24487ed3e1..f3357f3d85 100644
--- a/src/Runner/ErrorHandler.php
+++ b/src/Runner/ErrorHandler.php
@@ -24,6 +24,7 @@
 use const E_USER_NOTICE;
 use const E_USER_WARNING;
 use const E_WARNING;
+use function defined;
 use function error_reporting;
 use function restore_error_handler;
 use function set_error_handler;
@@ -63,6 +64,15 @@ public function __invoke(int $errorNumber, string $errorString, string $errorFil
             return false;
         }
 
+        /**
+         * E_STRICT is deprecated since PHP 8.4.
+         *
+         * @see https://github.com/sebastianbergmann/phpunit/issues/5956
+         */
+        if (defined('E_STRICT') && $errorNumber === @E_STRICT) {
+            $errorNumber = E_NOTICE;
+        }
+
         $test = Event\Code\TestMethodBuilder::fromCallStack();
 
         $ignoredByBaseline = $this->ignoredByBaseline($errorFile, $errorLine, $errorString);
@@ -70,7 +80,6 @@ public function __invoke(int $errorNumber, string $errorString, string $errorFil
 
         switch ($errorNumber) {
             case E_NOTICE:
-            case E_STRICT:
                 Event\Facade::emitter()->testTriggeredPhpNotice(
                     $test,
                     $errorString,