Billy Greer (born January 26, 1952) is the current bass guitarist for the band Kansas. He joined the band in 1985 in time for the Power album. He had previously worked with keyboardist/vocalist Steve Walsh in the band Streets, and works with his own band Seventh Key when not performing with Kansas. He also was a member of the brief 2009 Kansas side project "Native Window" along with Kansas members Phil Ehart, Richard Williams, and David Ragsdale.
In addition to performing, Billy manages his son's band "3 Story Fall" and produces their music.