The Bowring Treaty was a treaty signed between the British Empire and the Kingdom of Siam on 18 April 1855. The treaty had the primary effect of liberalizing foreign trade in Siam, and was signed by five Siamese plenipotentiaries (among them Wongsa Dhiraj Snid, one of the King's half-brothers) and Sir John Bowring, the British envoy and colonial governor of Hong Kong.