William "Buck" Washer (October 11, 1882 – December 8, 1955) was an American professional baseball pitcher. Washer played for the Philadelphia Phillies in the 1905 season. In one career game, he had a 0–0 record, giving up two runs, four hits, and also gave up five walks. He batted and threw right-handed.
Washer attended West Virginia University, where he played college baseball for the Mountaineers in 1902.
Washer was born and died in Akron, Ohio.