Jayavarman IX (Khmer: ជ័យវរ្ម័នទី៩), also known as Jayavarmadiparamesvara was sovereign of the Khmer Empire from 1327 to 1336.

Jayavarman IX was like his father, Indrajayavarman, a convinced Shivaite. According to the Cambodian Royal Chronicle, which named him "Sihanouk," ^[1] he was unintetionally assassinated in 1336 by the head of the royal gardens Trasak Paem, in an attempt to protect the garden, the king tells the assasian not to worry for killing his sovereign, as he was just following his duties, he then married his daughter and took his place on the throne. This narrative is probably legendary (we find a very similar one in Burmese history: see Nyaung-U Sawrahan).

This sovereign is the last king mentioned by inscriptions on the monuments. The last Sanskrit inscription of Cambodia dates from the reign of Jayavarman Parameshwara.