diff --git a/src/Header/ContentType.php b/src/Header/ContentType.php
index 8ffc7c6d..3b57df46 100644
--- a/src/Header/ContentType.php
+++ b/src/Header/ContentType.php
@@ -143,7 +143,7 @@ public function getType()
      */
     public function addParameter($name, $value)
     {
-        $name  = strtolower($name);
+        $name  = trim(strtolower($name));
         $value = (string) $value;
 
         if (! HeaderValue::isValid($name)) {
diff --git a/test/Header/ContentTypeTest.php b/test/Header/ContentTypeTest.php
index c7386a86..4d3f9b3a 100644
--- a/test/Header/ContentTypeTest.php
+++ b/test/Header/ContentTypeTest.php
@@ -222,6 +222,12 @@ public function testGetParameter()
         $this->assertSame('top', $header->getParameter('level'));
     }
 
+    public function testGetParameterWithSpaceTrimmed()
+    {
+        $header = ContentType::fromString('content-type: text/plain; level=top; name="logfile.log";');
+        $this->assertSame('logfile.log', $header->getParameter('name'));
+    }
+
     public function testGetParameterNotExists()
     {
         $header = ContentType::fromString('content-type: text/plain');