William "Billy" the Buffalo (debuted 2000 in Orchard Park, New York)^[1] is the official mascot of the NFL's Buffalo Bills. He is an 8-foot-tall (2.4 m) blue American buffalo and became the team's full-time mascot in 2000.^[1] He wears the uniform "number" BB (which is his initials).

Billy Buffalo was redesigned in 2018, with fan reception to the mascot's "makeover" being mixed.^[2][3] Jason Ballock, who wore the costume from 2006 to 2011, praised the design as more streamlined and "kid friendly".^[4]