Siamese–American Treaty of Amity and Commerce

Roberts Treaty with Siam
Treaty of Amity and Commerce between Siam and the United States
TypeTreaty
Drafted20 March 1833
Signed14 April 1836
LocationRoyal City of Sia-Yut'hia (commonly called Bangkok)
Effective24 June 1837
Expiration21 September 1921
NegotiatorsChau Phaya-Phraklang, Minister of State
Edmund Roberts, Minister of the United States of America
PartiesSiam
United States
LanguagesThai and English
Portuguese and Chinese annexed
Full text
Treaty of Amity and Commerce between Siam and the United States, 1833 at Wikisource

The Treaty of Amity and Commerce between His Majesty the Magnificent King of Siam and the United States of America, or Roberts Treaty of 1833, was the first treaty between Siam and the United States. It was also the first treaty that the US had with an Asian nation.

It established peaceful and friendly relations and commerce between the two states that have generally persisted since then. The treaty was signed on 20 March 1833 and, after ratification by both parties, it entered into force 14 April 1836. The treaty is no longer in force, having been replaced starting in 1921 by a series of subsequent treaties, but the successor treaty signed in 1966 remains in force. The 2017 edition of Treaties in Force, the official US government report listing treaties and other international agreements to which the United States has become a party and which are carried on the records of the Department of State, includes the treaty signed in 1966 and does not include this 1833 treaty.