diff --git a/wp-includes/category-template.php b/wp-includes/category-template.php
index 241e35de29..acb1625cde 100644
--- a/wp-includes/category-template.php
+++ b/wp-includes/category-template.php
@@ -331,7 +331,7 @@ function wp_dropdown_categories( $args = '' ) {
 		'name' => 'cat', 'id' => '',
 		'class' => 'postform', 'depth' => 0,
 		'tab_index' => 0, 'taxonomy' => 'category',
-		'hide_if_empty' => false
+		'hide_if_empty' => false, 'option_none_value' => -1
 	);
 
 	$defaults['selected'] = ( is_category() ) ? get_query_var( 'cat' ) : 0;
@@ -343,6 +343,7 @@ function wp_dropdown_categories( $args = '' ) {
 	}
 
 	$r = wp_parse_args( $args, $defaults );
+	$option_none_value = $r['option_none_value'];
 
 	if ( ! isset( $r['pad_counts'] ) && $r['show_count'] && $r['hierarchical'] ) {
 		$r['pad_counts'] = true;
@@ -381,7 +382,7 @@ function wp_dropdown_categories( $args = '' ) {
 		 * @param string $element Taxonomy element to list.
 		 */
 		$show_option_none = apply_filters( 'list_cats', $r['show_option_none'] );
-		$output .= "\t<option value='-1' selected='selected'>$show_option_none</option>\n";
+		$output .= "\t<option value='" . esc_attr( $option_none_value ) . "' selected='selected'>$show_option_none</option>\n";
 	}
 
 	if ( ! empty( $categories ) ) {
@@ -398,8 +399,8 @@ function wp_dropdown_categories( $args = '' ) {
 
 			/** This filter is documented in wp-includes/category-template.php */
 			$show_option_none = apply_filters( 'list_cats', $r['show_option_none'] );
-			$selected = ( '-1' === strval($r['selected']) ) ? " selected='selected'" : '';
-			$output .= "\t<option value='-1'$selected>$show_option_none</option>\n";
+			$selected = selected( $option_none_value, $r['selected'], false );
+			$output .= "\t<option value='" . esc_attr( $option_none_value ) . "'$selected>$show_option_none</option>\n";
 		}
 
 		if ( $r['hierarchical'] ) {
diff --git a/wp-includes/user.php b/wp-includes/user.php
index 3da96815cb..7eef1a57d0 100644
--- a/wp-includes/user.php
+++ b/wp-includes/user.php
@@ -1285,7 +1285,8 @@ function wp_dropdown_users( $args = '' ) {
 		'include' => '', 'exclude' => '', 'multi' => 0,
 		'show' => 'display_name', 'echo' => 1,
 		'selected' => 0, 'name' => 'user', 'class' => '', 'id' => '',
-		'blog_id' => $GLOBALS['blog_id'], 'who' => '', 'include_selected' => false
+		'blog_id' => $GLOBALS['blog_id'], 'who' => '', 'include_selected' => false,
+		'option_none_value' => -1
 	);
 
 	$defaults['selected'] = is_author() ? get_query_var( 'author' ) : 0;
@@ -1294,6 +1295,7 @@ function wp_dropdown_users( $args = '' ) {
 	$show = $r['show'];
 	$show_option_all = $r['show_option_all'];
 	$show_option_none = $r['show_option_none'];
+	$option_none_value = $r['option_none_value'];
 
 	$query_args = wp_array_slice_assoc( $r, array( 'blog_id', 'include', 'exclude', 'orderby', 'order', 'who' ) );
 	$query_args['fields'] = array( 'ID', 'user_login', $show );
@@ -1314,8 +1316,8 @@ function wp_dropdown_users( $args = '' ) {
 		}
 
 		if ( $show_option_none ) {
-			$_selected = selected( -1, $r['selected'], false );
-			$output .= "\t<option value='-1'$_selected>$show_option_none</option>\n";
+			$_selected = selected( $option_none_value, $r['selected'], false );
+			$output .= "\t<option value='" . esc_attr( $option_none_value ) . "'$_selected>$show_option_none</option>\n";
 		}
 
 		$found_selected = false;