diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8e26d88a..e2f9b9e6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 * feat: `PresetTransformer`.
 * fix: Typo in `RemoveOptionalDefinitionPass`
 * feat: Supports dynamic properties (including `stdClass`) on the target side.
+* fix(`Mapper`): Fix typehint.
 
 ## 1.0.0
 
diff --git a/src/Implementation/Mapper.php b/src/Implementation/Mapper.php
index 93c3e6d4..d6f9eb53 100644
--- a/src/Implementation/Mapper.php
+++ b/src/Implementation/Mapper.php
@@ -34,7 +34,7 @@ public function __construct(
      * @param class-string<T>|T $target
      * @return T
      */
-    public function map(mixed $source, object|string $target, ?Context $context = null): object
+    public function map(object $source, object|string $target, ?Context $context = null): object
     {
         if (is_string($target)) {
             $targetClass = $target;