Klaeng (Thai: แกลง, pronounced [klɛ̄ːŋ]) is a district (amphoe) on the coast of Rayong province, eastern Thailand.

[2] Its name "Klaeng" is believed to be a variant of the Chong word Ka-laeng (กะแล่ง), which means "walking catfish".

[3] Since the Ayutthaya period, Klaeng has been a place to gather people for war service.

[2] In the reign of King Rama V, Mueang Klaeng was a fourth class city under Monthon Chanthaburi.

Klaeng is a town (thesaban mueang) which covers parts of tambons Thang Kwian and Wang Wa.