Butterworth (population 108,000) is the principal town of Province Wellesley in the state of Penang in Malaysia. Butterworth is the site of the Malayan Railway station for Penang, and is linked to the island by ferry services and by a 13.5 km road bridge.

Butterworth is also the site of a Royal Malaysian Air Force airbase, the Headquarters of the Integrated Area Defence System of the Five Power Defence Arrangements.