diff --git a/wp-admin/options-permalink.php b/wp-admin/options-permalink.php
index 906361e8a8..345a4b067a 100644
--- a/wp-admin/options-permalink.php
+++ b/wp-admin/options-permalink.php
@@ -227,7 +227,7 @@ $structures = array(
 <?php
 $suffix = '';
 if ( ! $is_apache && ! $iis7_permalinks )
-	$suffix = 'index.php/';
+	$suffix = $wp_rewrite->index . '/';
 ?>
 <p><?php
 /* translators: %s is a placeholder that must come at the start of the URL path. */
diff --git a/wp-includes/canonical.php b/wp-includes/canonical.php
index 7cd12564f7..82ee38718a 100644
--- a/wp-includes/canonical.php
+++ b/wp-includes/canonical.php
@@ -272,9 +272,9 @@ function redirect_canonical( $requested_url = null, $do_redirect = true ) {
 				$redirect['query'] = remove_query_arg( 'cpage', $redirect['query'] );
 			}
 
-			$redirect['path'] = user_trailingslashit( preg_replace('|/index.php/?$|', '/', $redirect['path']) ); // strip off trailing /index.php/
-			if ( !empty( $addl_path ) && $wp_rewrite->using_index_permalinks() && strpos($redirect['path'], '/index.php/') === false )
-				$redirect['path'] = trailingslashit($redirect['path']) . 'index.php/';
+			$redirect['path'] = user_trailingslashit( preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/?$|', '/', $redirect['path']) ); // strip off trailing /index.php/
+			if ( !empty( $addl_path ) && $wp_rewrite->using_index_permalinks() && strpos($redirect['path'], '/' . $wp_rewrite->index . '/') === false )
+				$redirect['path'] = trailingslashit($redirect['path']) . $wp_rewrite->index . '/';
 			if ( !empty( $addl_path ) )
 				$redirect['path'] = trailingslashit($redirect['path']) . $addl_path;
 			$redirect_url = $redirect['scheme'] . '://' . $redirect['host'] . $redirect['path'];
@@ -324,7 +324,7 @@ function redirect_canonical( $requested_url = null, $do_redirect = true ) {
 		unset($redirect['port']);
 
 	// trailing /index.php
-	$redirect['path'] = preg_replace('|/index.php/*?$|', '/', $redirect['path']);
+	$redirect['path'] = preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/*?$|', '/', $redirect['path']);
 
 	// Remove trailing spaces from the path
 	$redirect['path'] = preg_replace( '#(%20| )+$#', '', $redirect['path'] );
@@ -345,7 +345,7 @@ function redirect_canonical( $requested_url = null, $do_redirect = true ) {
 
 	// strip /index.php/ when we're not using PATHINFO permalinks
 	if ( !$wp_rewrite->using_index_permalinks() )
-		$redirect['path'] = str_replace('/index.php/', '/', $redirect['path']);
+		$redirect['path'] = str_replace( '/' . $wp_rewrite->index . '/', '/', $redirect['path'] );
 
 	// trailing slashes
 	if ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() && !is_404() && (!is_front_page() || ( is_front_page() && (get_query_var('paged') > 1) ) ) ) {
diff --git a/wp-includes/link-template.php b/wp-includes/link-template.php
index de76f45aae..ad66602610 100644
--- a/wp-includes/link-template.php
+++ b/wp-includes/link-template.php
@@ -1449,13 +1449,13 @@ function get_pagenum_link($pagenum = 1, $escape = true ) {
 		}
 
 		$request = preg_replace( "|$wp_rewrite->pagination_base/\d+/?$|", '', $request);
-		$request = preg_replace( '|^index\.php|i', '', $request);
+		$request = preg_replace( '|^' . preg_quote( $wp_rewrite->index, '|' ) . '|i', '', $request);
 		$request = ltrim($request, '/');
 
 		$base = trailingslashit( get_bloginfo( 'url' ) );
 
 		if ( $wp_rewrite->using_index_permalinks() && ( $pagenum > 1 || '' != $request ) )
-			$base .= 'index.php/';
+			$base .= $wp_rewrite->index . '/';
 
 		if ( $pagenum > 1 ) {
 			$request = ( ( !empty( $request ) ) ? trailingslashit( $request ) : $request ) . user_trailingslashit( $wp_rewrite->pagination_base . "/" . $pagenum, 'paged' );
diff --git a/wp-includes/nav-menu-template.php b/wp-includes/nav-menu-template.php
index df5612d225..4fc614eb83 100644
--- a/wp-includes/nav-menu-template.php
+++ b/wp-includes/nav-menu-template.php
@@ -367,7 +367,7 @@ function _wp_menu_item_classes_by_context( &$menu_items ) {
 			$current_url = set_url_scheme( 'http://' . $_SERVER['HTTP_HOST'] . $_root_relative_current );
 			$raw_item_url = strpos( $menu_item->url, '#' ) ? substr( $menu_item->url, 0, strpos( $menu_item->url, '#' ) ) : $menu_item->url;
 			$item_url = untrailingslashit( $raw_item_url );
-			$_indexless_current = untrailingslashit( preg_replace( '/index.php$/', '', $current_url ) );
+			$_indexless_current = untrailingslashit( preg_replace( '/' . preg_quote( $wp_rewrite->index, '/' ) . '$/', '', $current_url ) );
 
 			if ( $raw_item_url && in_array( $item_url, array( $current_url, $_indexless_current, $_root_relative_current ) ) ) {
 				$classes[] = 'current-menu-item';
diff --git a/wp-includes/rewrite.php b/wp-includes/rewrite.php
index 486922a3d1..607a23d8c4 100644
--- a/wp-includes/rewrite.php
+++ b/wp-includes/rewrite.php
@@ -315,7 +315,7 @@ function url_to_postid($url) {
 
 	// Strip 'index.php/' if we're not using path info permalinks
 	if ( !$wp_rewrite->using_index_permalinks() )
-		$url = str_replace('index.php/', '', $url);
+		$url = str_replace( $wp_rewrite->index . '/', '', $url );
 
 	if ( false !== strpos($url, home_url()) ) {
 		// Chop off http://domain.com