diff --git a/src/Guzzle/Stream/PhpStreamRequestFactory.php b/src/Guzzle/Stream/PhpStreamRequestFactory.php
index 536cc1b2..c12fbb7c 100644
--- a/src/Guzzle/Stream/PhpStreamRequestFactory.php
+++ b/src/Guzzle/Stream/PhpStreamRequestFactory.php
@@ -9,6 +9,8 @@ use Guzzle\Http\Url;
 
 /**
  * Factory used to create fopen streams using PHP's http and https stream wrappers
+ *
+ * Note: PHP's http stream wrapper only supports streaming downloads. It does not support streaming uploads.
  */
 class PhpStreamRequestFactory implements StreamRequestFactoryInterface
 {