Bang Pa-In Royal Palace, also known as the Summer Palace, is a palace complex formerly used by the Thai kings. It lies beside the Chao Phraya River in Bang Pa-In district, Ayutthaya Province.

King Prasat Thong constructed the original complex in 1632, but it fell into disuse and became overgrown in the late 18th and early 19th centuries, until King Mongkut began to restore the site in the mid-19th century. Most of the present buildings were constructed between 1872 and 1889 by King Chulalongkorn.