Thomas Michael Jager (born October 6, 1964) is an American former competition swimmer.

Jager attended the University of California, Los Angeles (UCLA), and swam for coach Ron Ballatore's UCLA Bruins swimming and diving team in National Collegiate Athletic Association (NCAA) competition from 1983 to 1985.

Though yard-based races are only competed in the United States, Jager also held the world record in the 50 yard freestyle of 19.05 seconds from 1990 until 2005.

While under a swimming scholarship at the University of Iowa, his eldest sister Diane was an All-American swimmer.

His brother Bill qualified for Nationals while in high school and then went on to earn a full swimming scholarship at the University of Illinois.