add_editor_style( array|string $stylesheet = 'editor-style.css' )

Add callback for custom TinyMCE editor stylesheets.


The parameter $stylesheet is the name of the stylesheet, relative to the theme root. It also accepts an array of stylesheets. It is optional and defaults to ‘editor-style.css’.

This function automatically adds another stylesheet with -rtl prefix, e.g. editor-style-rtl.css. If that file doesn’t exist, it is removed before adding the stylesheet(s) to TinyMCE. If an array of stylesheets is passed to add_editor_style(), RTL is only added for the first stylesheet.

Since version 3.4 the TinyMCE body has .rtl CSS class. It is a better option to use that class and add any RTL styles to the main stylesheet.



(array|string) (Optional) Stylesheet name or array thereof, relative to theme root. Defaults to 'editor-style.css'

Default value: 'editor-style.css'


File: wp-includes/theme.php

function add_editor_style( $stylesheet = 'editor-style.css' ) {
	add_theme_support( 'editor-style' );

	if ( ! is_admin() )

	global $editor_styles;
	$editor_styles = (array) $editor_styles;
	$stylesheet    = (array) $stylesheet;
	if ( is_rtl() ) {
		$rtl_stylesheet = str_replace('.css', '-rtl.css', $stylesheet[0]);
		$stylesheet[] = $rtl_stylesheet;

	$editor_styles = array_merge( $editor_styles, $stylesheet );


Version Description
WP-3.0.0 Introduced.