is_child_theme() – Function | Developer.WordPress.org

Whether a child theme is in use.

Return

bool True if a child theme is in use, false otherwise.

function is_child_theme() {
	global $wp_stylesheet_path, $wp_template_path;

	return $wp_stylesheet_path !== $wp_template_path;
}

Used by	Description
get_block_asset_url()`wp-includes/blocks.php`	Gets the URL to a block asset.
WP_Site_Health::get_test_theme_version()`wp-admin/includes/class-wp-site-health.php`	Tests if themes are outdated, or unnecessary.
wp_get_active_and_valid_themes()`wp-includes/load.php`	Retrieves an array of active and valid themes.
WP_Customize_Manager::prepare_starter_content_attachments()`wp-includes/class-wp-customize-manager.php`	Prepares starter content attachments.
get_editor_stylesheets()`wp-includes/theme.php`	Retrieves any registered editor stylesheet URLs.
validate_current_theme()`wp-includes/theme.php`	Checks that the active theme has the required files.
locate_template()`wp-includes/template.php`	Retrieves the name of the highest priority template file that exists.

Version	Description
6.5.0	Makes use of global template variables.
3.0.0	Introduced.