Bangkok Mass Transit System Public Company Limited (BTSC, Thai: บริษัทระบบขนส่งมวลชนกรุงเทพ จำกัด (มหาชน)) is a Thai transport company, best known as the operator of Bangkok's BTS Skytrain. It is a majority-owned subsidiary of BTS Group Holdings (BTSG, previously known as Tanayong), and also operates the Bangkok BRT and the Gold Line.