diff --git a/src/Result.php b/src/Result.php
index 53728cf..b4aa6bb 100644
--- a/src/Result.php
+++ b/src/Result.php
@@ -18,10 +18,10 @@
 /**
  * Describes a Result
  *
- * @template T
+ * @template-covariant T
  * The Ok value
  *
- * @template E
+ * @template-covariant E
  * The Err value
  */
 abstract class Result
diff --git a/src/Result/Err.php b/src/Result/Err.php
index 1212f99..735774b 100644
--- a/src/Result/Err.php
+++ b/src/Result/Err.php
@@ -20,7 +20,7 @@
 /**
  * Err
  *
- * @template E
+ * @template-covariant E
  * The Err value
  *
  * @extends Result<mixed, E>
diff --git a/src/Result/Ok.php b/src/Result/Ok.php
index 81305a2..8e8e6b1 100644
--- a/src/Result/Ok.php
+++ b/src/Result/Ok.php
@@ -22,7 +22,7 @@
 /**
  * Ok
  *
- * @template T
+ * @template-covariant T
  * The Ok value
  *
  * @extends Result<T, mixed>