The Malayan Peoples' Socialist Front (Malay: Fron Sosialis Rakyat Malaya) or better known as Socialist Front (SF) was a left-wing coalition of Malaysian socialist parties. It is noted as the longest-standing opposition coalition in Malaysian general election history (11 years). The coalition was formed by Partai Rakyat (PR) and Parti Buruh Malaya (PBM) on Hari Merdeka. In 1964, National Convention Party (NCP) joined the coalition. PR left the coalition in 1965 and NCP soon become inactive. PBM, the only remaining party in SF, abandoned it on 10 January 1966 and reverted to its own banner. It took 21 years before another opposition coalition formed in Malaysia: Angkatan Perpaduan Ummah (APU) and Gagasan Rakyat (GR) in 1990.