Seth Trembly (born March 21, 1982) is a former American soccer defensive midfielder.
Trembly was part of the original 1999 class at the Bradenton Academy, where, as part of the Under-17 United States national team, he trained with Landon Donovan, DaMarcus Beasley, and Bobby Convey, as well as his future teammates at the Rapids, Kyle Beckerman and Jordan Cila.
Rather than go to college, Trembly signed a Project 40 contract with MLS, and was allocated to his hometown team, the Colorado Rapids, joining the club at the end of the 1999 season.
He scored two goal in his first season with Real Salt Lake, but did not play a minute in 2006 because of two tears to his ACL.
In 2017, Trembly was hired as an assistant coach for the women's soccer team at Utah Valley University.