Waeng (Thai: แว้ง, pronounced [wɛ́ːŋ]) is the southernmost district (amphoe) of Narathiwat province, southern Thailand.

In 1935 a minor district (king amphoe) covering the central part of Tomo was established and named Pacho (ปาโจ).

[1] In 1939 the minor district received the name "Tomo" because it contained the sub-district named "Tomo", and the parent district was renamed "Waeng".

[2] In 1953 the minor district Tomo was abolished and included in Waeng again.

The district is divided into six sub-districts (tambons), which are further subdivided into 45 villages (mubans).