Phimeanakas (Khmer: ប្រាសាទភិមានអាកាស, Prasat Phimean Akas, 'celestial temple') or Vimeanakas (Khmer: ប្រាសាទវិមានអាកាស, Prasat Vimean Akas) at Angkor, Cambodia, is a Hindu temple in the Khleang style, built at the end of the 10th century, during the reign of Rajendravarman (from 941-968), then completed by Suryavarman I in the shape of a three tier pyramid as a Hindu temple. On top of the pyramid there was a tower, while on the edge of top platform there are galleries. Phimeanakas is located inside the walled enclosure of the Royal Palace of Angkor Thom north of Baphuon.

The temple was the focal point of Suryavarman I's capital.The buildings there from his reign are enclosed by a wall 600 by 250 m, with five gopuram, and include the Southern and Northern Khleangs.

The tower must originally have been crowned with a golden pinnacle, as Zhou Daguan described it in his report. According to legend, the king spent the first watch of every night with a woman thought to represent a Nāga in the tower, during that time, not even the queen was permitted to intrude. Only in the second watch the king returned to his palace with the queen. If the naga who was the supreme land owner of Khmer land did not show up for a night, the king's day would be numbered, if the king did not show up, calamity would strike his land.

One of the stele states Jayavarman VII, while on a military expedition in Champa, learned that his father Dharanindravarman II had died, and "returned in great haste to aid King Yasovarman II. Jayavarman's second wife, Indradevi, "...composed in impeccable Sanskrit the inscription...panegyric of her sister" Jayarajadevi, which included biographical detail of Jayavarman VII.

Phimeanakas is located inside the enclosure of the Royal Palace of Angkor Thom north of Baphuon 

Phimeanakas can be reached on foot either from Prah Palilay or from the Terrace of the Elephants. Pass through the gap in the south side of the enclosing wall of Prah and walk straight for about 200 meters (656 feet); turn left to the east and right at the first path, then follow it until you reach the temple. Or walk across the Terrace of Elephants at the entrance closest to the Victory Gate road and walk through an entry tower; then follow the path until you reach the temple.

Alternatively, return to the main road beside the Terrace of the Leper King, turn right and turn right again on the first road, then drive straight to the monument.

Enter Phimeanakas from the east entrance. It is possible to leave by the south gate and walk through a space in the enclosing wall to the east entrance of the Baphuon.