James Marbury "Sammy" Holbrook (July 17, 1910 - April 10, 1991) was an American Major League Baseballcatcher. He played one season in the majors, in 1935, for the Washington Senators. That year, he served as the primary backup to starting catcher Cliff Bolton.
Holbrook's minor league baseball career spanned 14 seasons, from 1929 until 1942. In 1939, he served as player-manager of the Federalsburg A's of the Eastern Shore League. Holbrook batted .361 in 98 games while leading the team to the league championship in his only season as manager.