Sisowath Kossamak (Khmer: ?????????? ?????; 9 April 1904 – 27 April 1975) was the Queen consort of Cambodia by marriage to King Norodom Suramarit from 1955 to his death in 1960.
She then became co-head of state with her only son, Norodom Sihanouk, from 1960 to 1970.
Sisowath Kossamak was born Princess of Cambodia as the daughter of King Sisowath Monivong and his wife Norodom Kanviman Norleak Tevi.
Her official title was Preah Mohasatreiyani Sisowath Monivong Kossamak Nearirath Serey Vathana (Khmer: ?????????????????? ?????????????????? ?????????????????????????).
Upon the death of Monivong in 1941, Sihanouk took the throne.
In 1955, he abdicated in favor of his father Suramarit, who then reigned for five years.
After her husband's death, Kossamak became the symbol and representative of the monarchy while Sihanouk assumed a role equal to that of a monarch.
Both were overthrown in a 1970 coup, and they went into exile in China.