diff --git a/wp-includes/compat.php b/wp-includes/compat.php
index d6006a481..4448708df 100644
--- a/wp-includes/compat.php
+++ b/wp-includes/compat.php
@@ -118,4 +118,11 @@ if ( !function_exists('_') ) {
 	}
 }
 
+// Added in PHP 5.0
+if (!function_exists('stripos')) {
+	function stripos($haystack, $needle, $offset = 0) {
+		return strpos(strtolower($haystack), strtolower($needle), $offset);
+	}
+}
+
 ?>