William Raymond Brennan (born January 15, 1963) is a former pitcher in Major League Baseball.

Brennan attended Mercer University and was signed as an undrafted free agent by the Los Angeles Dodgers on September 1, 1984.

He appeared in four games for the Dodgers during their championship year of 1988, making two starts.

He was back with the Dukes for 1989 and then moved around, playing for the Tucson Toros (Houston Astros), Harrisburg Senators (Montreal Expos), Toledo Mud Hens (Detroit Tigers) and Iowa Cubs, before getting another chance in the bigs with the Chicago Cubs in 1993.

This biographical article relating to an American baseball pitcher born in the 1960s is a stub.