Jayavarman I (Khmer: ជ័យវរ្ម័នទី១) ruled the pre-Angkor realm known by the Chinese as Chenla (or Zhenla), one of the predecessor polities of the Angkor Empire.
Jayavarman means "victorious protector". "Jaya" literally means "victorious", and "varman", a suffix used in the reign-names of the overlords of Funan and Chenla, and throughout Cambodian history, means “armour”; hence, “protection”.
The great-grandson of Isanavarman I, he succeeded his father Candravarman and ruled from approximately 657 until after 690. His palace was located at Purandarapura, at the northern end of the Tonle Sap.
Over the course of his reign, and that of his predecessors Bhavavarman II and Candravarman, the Khmer kings' power began to be consolidated in the areas previously controlled by the Funan culture, but there was much fighting among local overlords who ruled different parts of Cambodia.
Jayavarman I left no male heirs, and his daughter, Jayadevi, succeeded him as queen (she was the only ancient Khmer queen). He was grandfather to Harshavarman I (reign 910 – 923).