Simwonsa (Korean: 심원사; Hanja: 深源寺) is an historic Korean Buddhist temple located in Sangyang-ri, Pakchon County, North Pyongan Province, North Korea. It is listed as the 54th National Treasure of North Korea.^[1]

The temple was built in the ninth century and rebuilt in 1368. It features examples of painting and wood processing techniques used by craftsmen of the era.^[2]

A carving on the temple says it was built by Hyon Uk (786-868). The temple site has three buildings, Pogwang Shrine (the main building), the Chongphung and the Hyangro Pavilions. The Pogwang site is described as a "colorfully painted building ... decorated with dragon, phoenix and other sculptures". On the wall of the Chongphung Pavilion is a wooden fish 2.5 meters long, weighing 100 kilograms.^[3]