James Harold Umbarger (February 17, 1953 – August 5, 2024) was an American professional baseball pitcher.

Umbarger made his major league debut in April, of 1975, with the Rangers, and had a successful rookie season for the team, going 8–7 in 56 games (12 of them starts, with 2 shutouts), with a 4.12 ERA.

Prior to the 1977 season, Umbarger was traded to the Oakland Athletics, along with Rodney Scott, for outfielder Claudell Washington.

He finished the 1977 season with the Rangers and returned for the 1978 campaign, appearing in 32 games and posting a 4.88 ERA.

In 1981, he pitched 10 innings of scoreless relief in the longest professional baseball game ever played, a 33-inning marathon between Pawtucket and Rochester.