James Thomas "Deacon" McGuire (November 18, 1863 – October 31, 1936) was an American professional baseball player, manager and coach whose career spanned the years 1883 to 1915. He played 26 seasons in Major League Baseball, principally as a catcher, for 11 different major league clubs. His longest stretches were with the Washington Statesmen/Senators (901 games, 1892–99), Brooklyn Superbas (202 games, 1899–1901) and New York Highlanders (225 games, 1904–07). He played on Brooklyn teams that won National League pennants in 1899 and 1900.

McGuire was the most durable catcher of his era, setting major league catching records for most career games caught (1,612), putouts (6,856), assists (1,860), double plays turned (143), runners caught stealing (1,459), and stolen bases allowed (2,529). His assist, caught stealing, and stolen bases allowed totals remain current major league records. During his major league career, he also compiled a .278 batting average, .341 on-base percentage, 770 runs scored, 1,750 hits, 300 doubles, 79 triples, 45 home runs, 840 RBIs and 118 stolen bases. His best season was 1895 when he caught a major league record 133 games and compiled a .336 batting average with 10 home runs, 97 RBIs and 17 stolen bases.

McGuire was also the manager of the Washington Senators (1898), Boston Red Sox (1907–08) and Cleveland Indians (1909–11). He compiled a 210–287 (.423) as a major league manager.