diff --git a/src/Resolver/Directory.php b/src/Resolver/Directory.php
index 53b15a8..d15448a 100644
--- a/src/Resolver/Directory.php
+++ b/src/Resolver/Directory.php
@@ -68,6 +68,8 @@ public function resolve($definition)
 
             $response->setStream(fopen($path, 'r'));
             $response->getHeaders()->addHeader(new ContentType($mimeType));
+            // Enforce best practice and make sure static assets are cacheable
+            $response->getHeaders()->addHeaderLine('Cache-Control', 'max-age=31557600');
         }
 
         return $response;
diff --git a/test/Resolver/DirectoryTest.php b/test/Resolver/DirectoryTest.php
index 97bcf15..c03754f 100644
--- a/test/Resolver/DirectoryTest.php
+++ b/test/Resolver/DirectoryTest.php
@@ -100,6 +100,7 @@ public function testResolve(): void
         verify($result)->is()->instanceOf(Response::class);
         verify($result->getStatusCode())->is()->sameAs(200);
         verify($result->getHeaders()->get('Content-Type')->getFieldValue())->is()->sameAs('text/plain');
+        verify($result->getHeaders()->get('Cache-Control')->getFieldValue())->is()->sameAs('max-age=31557600');
         verify($result->getBody())->is()->equalToFile(__DIR__ . '/_data/sample.txt');
     }