Prince Sisowath Sirik Matak (January 22, 1914 — April 21, 1975) was a member of the Cambodian royal family, the Varman dynasty, under the House of Sisowath.
Sirik Matak was mainly notable for his involvement in Cambodian politics, particularly for his involvement in the 1970 right-wing coup against his cousin, Prince Norodom Sihanouk, and for his subsequent establishment, along with Lon Nol, of the Khmer Republic.
Sirik Matak was born in Phnom Penh, and was a member of the Sisowath branch of the Varman Dynasty, being the great-grandson of Sisowath of Cambodia. He was recruited into the colonial civil service in 1930.
Under the colonial French-imposed constitution, any member of the Norodom or Sisowath branches of the family could be selected as king, and Sirik Matak was therefore one of the possible contenders to the Cambodian throne. In 1941, after the death of King Sisowath Monivong, the French authorities selected Sirik Matak's cousin Norodom Sihanouk to be King, believing him to be relatively pliant.