diff --git a/assets/.htaccess b/assets/.htaccess
index dc0e7f8..0d1426e 100644
--- a/assets/.htaccess
+++ b/assets/.htaccess
@@ -1,5 +1,6 @@
 # Custom error pages
 ErrorDocument 403 /errors/403.php
 ErrorDocument 404 /errors/404.php
+ErrorDocument 405 /errors/405.php
 ErrorDocument 500 /errors/500.php
 ErrorDocument 504 /errors/504.php
diff --git a/assets/errors/405.php b/assets/errors/405.php
new file mode 100644
index 0000000..4d5a6ec
--- /dev/null
+++ b/assets/errors/405.php
@@ -0,0 +1,18 @@
+<?php
+$COMMONS = $_SERVER['DOCUMENT_ROOT'] . "/../common";
+
+include_once($COMMONS."/header.php");
+
+display_header("405: Method not allowed");
+?>
+
+<article>
+<h2>405: Method Not Allowed</h2>
+<div class="centered-container">
+<img src="https://assets.zdenekborovec.cz/upload/39486004aa605167cdda6623a4a3fa6d/7da36b469b34cc1008639612f0c17e21/d077e6ed1bd1a560a718590ae609422c.gif" alt="GIF of a cat shaking its head.">
+</div>
+</article>
+
+<?php
+include_once($COMMONS."/footer.php");
+?>
diff --git a/docs/www/.htaccess b/docs/www/.htaccess
index 2ded313..2359b1b 100644
--- a/docs/www/.htaccess
+++ b/docs/www/.htaccess
@@ -15,5 +15,6 @@ RewriteRule ^([^\.]+)/$ $1.php
 # Custom error pages
 ErrorDocument 403 /errors/403.php
 ErrorDocument 404 /errors/404.php
+ErrorDocument 405 /errors/405.php
 ErrorDocument 500 /errors/500.php
 ErrorDocument 503 /errors/503.php
diff --git a/docs/www/errors/405.php b/docs/www/errors/405.php
new file mode 100644
index 0000000..4d5a6ec
--- /dev/null
+++ b/docs/www/errors/405.php
@@ -0,0 +1,18 @@
+<?php
+$COMMONS = $_SERVER['DOCUMENT_ROOT'] . "/../common";
+
+include_once($COMMONS."/header.php");
+
+display_header("405: Method not allowed");
+?>
+
+<article>
+<h2>405: Method Not Allowed</h2>
+<div class="centered-container">
+<img src="https://assets.zdenekborovec.cz/upload/39486004aa605167cdda6623a4a3fa6d/7da36b469b34cc1008639612f0c17e21/d077e6ed1bd1a560a718590ae609422c.gif" alt="GIF of a cat shaking its head.">
+</div>
+</article>
+
+<?php
+include_once($COMMONS."/footer.php");
+?>