William Allen Blair (born December 18, 1965) is an American former right-handed pitcher in Major League Baseball and current pitching coach for the Dayton Dragons.

Blair was then traded to the Houston Astros with Eddie Taubensee for Kenny Lofton and Dave Rohde.

After the Rockies (1993–1994), he played for the San Diego Padres (1995–1996), Detroit Tigers (1997, 1999–2001), Arizona Diamondbacks (1998), and New York Mets (1998).

In 1999, Blair was the starting pitcher for the final Opening Day in Tiger Stadium history.

On January 23, 2025, he was announced as the pitching coach for the Dayton Dragons, the High-A affiliate of the Cincinnati Reds.