The Siam Society under Royal Patronage was founded in 1904 in cooperation with Thai and foreign scholars to promote knowledge of Thailand and its surrounding region.

The Society premises on Asoke Montri Road in Bangkok house a library that has a unique collection including manuscripts and rare books. The Kamthieng House, a precious example of northern Thai architecture, houses a folk museum. Study trips are made to historical sites, cultural events, and nature sites in all corners of Thailand and overseas. Lectures are organized several times a month on a wide range of topics. The Journal of the Siam Society and the Natural History Bulletin are published annually and distributed free to members. The Society also publishes scholarly books; stages performances of music, dance, and drama; hosts exhibitions and conferences; and is involved in projects of cultural preservation.

Today, the Siam Society has a membership drawn from a broad spectrum of Thais and foreigners, and continues to operate as a non-profit organization dedicated to its founding cause.