Si Votha (also spelled Si Vattha) (c. 1841 - 31 December 1891) was a Cambodian prince who was briefly a contender for the throne. He spent his entire life fighting his half brother King Norodom for the throne.
Si Votha was a grandson of King Ang Eng (1772–1796) and a son of King Ang Duong. His biographical notes only record that he had a daughter named Neak Ang Mechas (Princess) Ang Duong Rath Votha. Si Votha had two half-brothers, Norodom and Sisowath, with Norodom being the king's chosen heir. Upon King Ang Duong's death, a succession struggle ensued, with Si Votha attempting to take power while his half brother, Norodom was occupied with a rebellion, eventually Norodom gained the upper hand when he gained the backing of Sisowath.