The Supreme Patriarch of Cambodia (Pali: Sangharāja; Khmer: សម្តេចព្រះសង្ឃរាជ, pronounced [sɑmdac preah sɑŋ riec]) is the de facto leader of Buddhism in Cambodia.
The titles for the Cambodian Supreme Patriarchs are derived from Pali. The full official title of the Supreme Patriarch of the Maha Nikaya is Samdech Preah Sumedhādhipati (Khmer: សម្តេច ព្រះ សុមេធាធិបតី); sumedhādhipati means 'wise lord'. In letters with King-Father Norodom Sihanouk, the following title is used for the Great Supreme Patriarch Tep Vong: Samdech Preah Agga Mahā Sangharājādhipati (Khmer: សម្តេច ព្រះ អគ្គមហាសង្ឃរាជាធិបតី); which is translated as 'foremost great supreme patriarch leader'.
The full official title of the Supreme Patriarch of the Dhammayuttika Nikaya is Samdech Preah Aphiserei Sukonthea Mohasangreacheathipadei (Abhisirī Sugandhā Mahāsangharājādhipati) (Khmer: សម្តេច ព្រះ អភិសិរី សុគន្ធា មហាសង្ឃរាជាធិបតី). This title means 'Of Higher Merit and Pure Virtue, Great Supreme Patriarch Leader'. In letters with King-Father Sihanouk, an abbreviated title is used in the valediction: Samdech Preah Sangreach (Khmer: សម្តេច ព្រះ សង្ឃរាជ).'
Between 1855 and 1981, there were two Supreme Patriarchs in the Kingdom of Cambodia: one for the Cambodian branch of the Thai Dhammayuttika Nikaya order, and one for the Maha Nikaya. In 1981, under the supervision of the Vietnamese-backed People's Republic of Kampuchea, Venerable Tep Vong was elected Supreme Patriarch of a new, unified sangha modelled on the Vietnamese Theravada Buddhist Sangha Congregation.