Gregory Walter Graffin (born November 6, 1964) is an American singer, songwriter, and evolutionary biologist. He is most recognized as the lead vocalist, songwriter, and only constant member of punk rock band Bad Religion, which he co-founded in 1979. He embarked on a solo career in 1997, when he released the album American Lesion. His follow-up album, Cold as the Clay, was released nine years later. His newest solo work is Millport, released in 2017.
Graffin obtained his PhD in zoology at Cornell University and has lectured courses in natural sciences at both the University of California, Los Angeles and at Cornell University.