Robert Alexander Unglaub (July 31, 1881 – November 29, 1916) was an American first baseman and utility infielder in Major League Baseball who played for the New York Highlanders, Boston Americans, and Washington Senators.
Born in Baltimore, Maryland, he attended the University of Maryland, and in 1904 he was offered his first shot at the major leagues, being signed by the Highlanders. Due to blood poisoning, he was only able to play six games, and was sent to the Americans for Patsy Dougherty, which some people perceived as the American League's attempt to increase competition against the National League's New York Giants. He didn't become a regular player until the 1907 season when he also served as manager of the Red Sox, replacing George Huff. He went 9–20 (.310) in his only managerial stint.
Unglaub had a series of minor league managerial jobs, and in 1916, while supervising repair work on a locomotive, he was killed in an accident in his hometown of Baltimore at age 35. He was laid to rest at Sunny Ridge Memorial Park in Crisfield, Maryland.