Merle Colby Allin, Jr. (born September 1, 1953) is an American electric bass guitar player. He is the older brother of the late punk rock singer/songwriter GG Allin.
Allin played bass for three main groups that featured GG Allin: Malpractice, The AIDS Brigade and The Murder Junkies. He currently continues the Murder Junkies, his brother's last backing band, with original drummer Donald ("Dino Sex") Sachs, and a varying line-up of younger members.
Allin was also bass player in late 70's Boston punk group Thrills (a.k.a. City Thrills), who released several singles and were the subject of a later CD discography. He subsequently joined the band Cheater Slicks, and played bass guitar on their debut album, "On Your Knees."