Wat Phutthaisawan (Thai: วัดพุทไธศวรรย์; also spelled: Phutthai Sawan or Buddhaisawan; literally: "Monastery of Buddhist Kingship") is a historic Thai Buddhist temple in Phra Nakhon Si Ayutthaya Province, central Thailand, and is part of Ayutthaya Historical Park.

The temple is situated on the west bank of Chao Phraya River, opposite to south of Ayutthaya City.

The most striking aspect of this temple is a white prang (Khmer-style pagoda), located in the middle of the ancient compound and built on an indented pedestal protruding towards the north and south.

The inner wall of the cloister houses rows of golden glittering Sukhothai Buddha images on decorated bases.

In this event, the temple and neighbouring Saint Joseph Catholic Church was the site of the fortress of the converts to prevent the invasion of the Burmese army.