Siagian is one of Toba Batak clans originating in North Sumatra, Indonesia. People of this clan bear the clan's name as their surname. Notable people of this clan include: Bachtiar Siagian (1923–2002), Indonesian film director and scriptwriter Batara Goempar Siagian (born 1985), Indonesian cinematographer Sabam Siagian (1932–2016), Indonesian journalist