Phanom Thuan (Thai: พนมทวน, pronounced [pʰā.nōm tʰūa̯n]) is a district (amphoe) in the eastern part of Kanchanaburi province, western central Thailand.

At the archaeological site of Ban Don Ta Phet many artifacts were found in a 4th century cemetery, which indicated trade relations with India, Vietnam, and the Philippines.

At the Don Chedi archaeological site an excavation by the Fine Arts Department in 1982 recovered many human skeletons as well as elephant bones and swords.

Thus this site might even have been the location of the famous battle of King Naresuan against the Burmese crown-prince, most commonly assigned to the Don Chedi district nearby.

When in 1831 King Rama III relocated the center of Kanchanaburi and readjusted its extent, Nuea district was renamed to Ban Thuan, covering the mountainous areas and the northward flowing river.