Ak Yum (Khmer: ប្រាសាទអកយំ) is an ancient temple in the Angkor region of Cambodia. [2]: 350,352 Helen Jessup dates from the temple until the 8th century and states that it is the oldest known example of "temple mountain" in Southeast Asia.

The origins and repair history of the temple are not clear. Stone bearing inscriptions, including one with a date corresponding to Saturday, June 10, 674 AD during the reign of King Jayavarman I. The first structure on the site was a single-room brick sanctuary, probably built in the latter part of the eighth century . It was later remade into a larger pillar pyramid structure, with a base of approximately 100 square meters. The expansion probably occurred in the early 9th century during the reign of King Jayavarman II, who is widely recognized as the founder of the Khmer Empire. When the West Baray Reservoir was built in the 11th century, Ak Yum was partially buried by the southern dike. [Citation needed] The site was excavated in 1932 under the direction of archaeologist George Trouvé.