diff --git a/system/core/Input.php b/system/core/Input.php
index e1319be..d896495 100644
--- a/system/core/Input.php
+++ b/system/core/Input.php
@@ -803,7 +803,7 @@
 
 		if ( ! isset($headers))
 		{
-			empty($this->headers) OR $this->request_headers();
+			empty($this->headers) && $this->request_headers();
 			foreach ($this->headers as $key => $value)
 			{
 				$headers[strtolower($key)] = $value;
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 061efe8..de9c957 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -16,6 +16,7 @@
 
 -  Fixed a bug (#2284) - :doc:`Database <database/index>` method ``protect_identifiers()`` breaks when :doc:`Query Builder <database/query_builder>` isn't enabled.
 -  Fixed a bug (#4052) - :doc:`Routing <general/routing>` with anonymous functions didn't work for routes that don't use regular expressions.
+-  Fixed a bug (#4056) - :doc:`Input Library <libraries/input>` method ``get_request_header()`` could not return a value unless ``request_headers()`` was called beforehand.
 
 Version 3.0.1
 =============