Alexandre, Chevalier de Chaumont (1640 – Paris, January 28, 1710) was the first French ambassador for King Louis XIV in Siam. He was accompanied on his mission by Abbé de Choisy, the Jesuit Guy Tachard, and Father Bénigne Vachet of the Société des Missions Étrangères de Paris. He was also bringing back to Siam the two ambassadors of the 1684 First Siamese Embassy to France.
He tried without success to convert King Narai the Great to Catholicism and to conclude significant commercial treaties.
He is, above all, remembered for his memoirs describing life in 17th century Siam.