Oscar William Westerberg (July 8, 1882, Alameda, California – April 17, 1909, Alameda, California) was a Major League Baseball shortstop who played for the Boston Doves in 1907. Prior to playing professionally, he attended Saint Mary's College of California. He made his debut on September 5, 1907 and played his final game on September 7, 1907. In that time, he appeared in two games, collecting two hits in six at-bats for a .333 batting average. He also handled six chances in the field without committing any errors.