Butterworth is the principal town of Seberang Perai in the state of Penang in Malaysia. Named after William John Butterworth, Governor of the Straits Settlements (1843–1855), Butterworth was established in the mid-19th century as a landing place across the channel from the capital of Penang, George Town. The town has a population of 107,591 and it is also known unofficially in Malay as Bagan, meaning "jetty". Butterworth is the site of the Malayan Railway station for Penang, and is linked to the island by the Penang Ferry Service and by the 13.5 km Penang Bridge.
The Penang Bird Park, a landscaped park with over 300 species of birds from all over Southeast Asia, is situated in this town. Butterworth is also the location of a Royal Malaysian Air Force station, RMAF Butterworth, formerly operated by the Royal Air Force and the Royal Australian Air Force, and is now the Headquarters of the Integrated Area Defence System (HQIADS) of the Five Power Defence Arrangements.
Butterworth will be the site of an integrated transport hub called Penang Sentral, which will integrate rail, ferry and bus transport. It is the parliamentary seat of Bagan and its Member of Parliament is the current Chief Minister of Penang, Lim Guan Eng