diff --git a/phpBB/includes/acp/acp_bbcodes.php b/phpBB/includes/acp/acp_bbcodes.php
index e21e2fb37f..dd1897ecbd 100644
--- a/phpBB/includes/acp/acp_bbcodes.php
+++ b/phpBB/includes/acp/acp_bbcodes.php
@@ -134,6 +134,11 @@ class acp_bbcodes
 					}
 				}
 
+				if (!preg_match('#\[' . $data['bbcode_tag'] .'].*?\[/' . $data['bbcode_tag'] . ']#s', $bbcode_match))
+				{
+					trigger_error($user->lang['BBCODE_OPEN_ENDED_TAG'] . adm_back_link($this->u_action), E_USER_WARNING);
+				}
+
 				$sql_ary = array(
 					'bbcode_tag'				=> $data['bbcode_tag'],
 					'bbcode_match'				=> $bbcode_match,
diff --git a/phpBB/language/en/acp/posting.php b/phpBB/language/en/acp/posting.php
index 5e396fc83c..13dae541ac 100644
--- a/phpBB/language/en/acp/posting.php
+++ b/phpBB/language/en/acp/posting.php
@@ -38,11 +38,12 @@ $lang = array_merge($lang, array(
 
 	'BBCODE_ADDED'				=> 'BBCode added successfully.',
 	'BBCODE_EDITED'				=> 'BBCode edited successfully.',
-	'BBCODE_INVALID_TAG_NAME'	=> 'The BBCode tag name that you selected already exists.',
 	'BBCODE_NOT_EXIST'			=> 'The BBCode you selected does not exist.',
 	'BBCODE_HELPLINE'			=> 'Helpline',
 	'BBCODE_HELPLINE_EXPLAIN'	=> 'This field contains the mouseover text of the BBCode',
 	'BBCODE_HELPLINE_TEXT'		=> 'Helpline text',
+	'BBCODE_INVALID_TAG_NAME'	=> 'The BBCode tag name that you selected already exists.',
+	'BBCODE_OPEN_ENDED_TAG'		=> 'Your custom BBCode must contain both an opening and a closing tag.',
 	'BBCODE_TAG'				=> 'Tag',
 	'BBCODE_TAG_TOO_LONG'		=> 'The tag definition that you have entered is too long, please shorten your tag definition.',
 	'BBCODE_USAGE'				=> 'BBCode usage',