get_blog_option( int $id, string $option, mixed $default_value = false ): mixed

Retrieves option value for a given blog id based on name of option.


If the option does not exist or does not have a value, then the return value will be false. This is useful to check whether you need to install an option and is commonly used during installation of plugin options and to test whether upgrading is required.

If the option was serialized then it will be unserialized when it is returned.


A blog ID. Can be null to refer to the current blog.
Name of option to retrieve. Expected to not be SQL-escaped.
Default value to return if the option does not exist.



mixed Value set for the option.

More Information

There is a filter called ‘blog_option_$option‘ with the $option being replaced with the option name. The filter takes two parameters: $value and $blog_id. It returns $value. The ‘option_$option‘ filter in get_option() is not called.


function get_blog_option( $id, $option, $default_value = false ) {
	$id = (int) $id;

	if ( empty( $id ) ) {
		$id = get_current_blog_id();

	if ( get_current_blog_id() == $id ) {
		return get_option( $option, $default_value );

	switch_to_blog( $id );
	$value = get_option( $option, $default_value );

	 * Filters a blog option value.
	 * The dynamic portion of the hook name, `$option`, refers to the blog option name.
	 * @since 3.5.0
	 * @param string  $value The option value.
	 * @param int     $id    Blog ID.
	return apply_filters( "blog_option_{$option}", $value, $id );


apply_filters( “blog_option_{$option}”, string $value, int $id )

Filters a blog option value.


MU (3.0.0)Introduced.

User Contributed Notes

You must log in before being able to contribute a note or feedback.