Wat Rajasittharam Rajaworawihara ( Wat Rajasit) is located close to the Charoenpart Bridge on Isaraphap road in Thonburi. The temple dated from the Ayutthaya Period and it was called originally Wat Phrab. King Rama I ordered the construction of a new temple next to Wat Phrab and the two temples were combined as one. In 1808 the temple was again renovated.

King Rama III resided at this temple while he has a monk, and after he ascended the throne, he ordered another renovation of the temple.

Wat Rajasittharam has several important buildings. The Phra Tamnak Chan was constructed by King Rama II for the future King Rama III when he was a monk. It is a small building with two rooms, the ground floor is of bricks and mortar, while the upper floor is of sandalwood (chan). The apex of gable ( Cho fa, bai raka ) is beautifully decorated with mirrors. King Rama III subsequently had the building moved next to a Chinese-style building. The sandalwood, which had become rotten, was replaced with other types of wood such as teng (shorea), rang (dipterocarpaceae) and teak so that only part of the original sandalwood remains.

The Phra Ubosot was reconstructed in the Third Reign when the temple was completely renovated. Murals in the Phra Ubosot depict scene of a royal procession on land but the paintings have badly deteriorated.