diff --git a/wp-admin/options-general.php b/wp-admin/options-general.php
index 3fc77ddaf8..fdae33a60b 100644
--- a/wp-admin/options-general.php
+++ b/wp-admin/options-general.php
@@ -230,12 +230,12 @@ if ( empty($tzstring) ) { // Create a UTC+- zone if no timezone string exists
 	<fieldset><legend class="screen-reader-text"><span><?php _e('Date Format') ?></span></legend>
 <?php
 
-	$date_formats = apply_filters( 'date_formats', array(
+	$date_formats = array_unique( apply_filters( 'date_formats', array(
 		__('F j, Y'),
 		'Y/m/d',
 		'm/d/Y',
 		'd/m/Y',
-	) );
+	) ) );
 
 	$custom = true;
 
@@ -263,11 +263,11 @@ if ( empty($tzstring) ) { // Create a UTC+- zone if no timezone string exists
 	<fieldset><legend class="screen-reader-text"><span><?php _e('Time Format') ?></span></legend>
 <?php
 
-	$time_formats = apply_filters( 'time_formats', array(
+	$time_formats = array_unique( apply_filters( 'time_formats', array(
 		__('g:i a'),
 		'g:i A',
 		'H:i',
-	) );
+	) ) );
 
 	$custom = true;