Robert Hamilton Hyatt (November 1, 1884 – September 11, 1963) was an American professional baseball first baseman. He played in Major League Baseball (MLB) from 1909 to 1918 for the Pittsburgh Pirates, St. Louis Cardinals, and New York Yankees. Hyatt started his professional baseball career with the Vancouver Beavers of the Northwestern League. In 1908, he hit .323 with 15 home runs; he led the league in hits, home runs, and runs scored. He was purchased by the Pittsburgh Pirates after the season.