Sepp Kuss (born September 13, 1994) is an American professional cyclist who rides for UCI WorldTeam Visma–Lease a Bike. He won the 2023 Vuelta a España, becoming the first American to win a Grand Tour since Chris Horner in 2013. Kuss is the second cyclist to win a Grand Tour and finish all three Grand Tours in a single season, after Gastone Nencini in 1957.

Born in Durango, Colorado, Kuss started as a mountain biker and won three collegiate national championships at the University of Colorado Boulder. After transitioning to road cycling in 2016, Kuss progressed from amateur races to the WorldTour within two years, establishing himself as a climbing specialist. Media outlets have described Kuss as a "super-domestique" for his support of team leaders Primož Roglič and Jonas Vingegaard in winning a combined six Grand Tours. Kuss won individual stages at the Tour de France (2021) and Vuelta a España (2019, 2023) as well as the general classification at the 2018 Tour of Utah and 2024 Vuelta a Burgos. His 2023 Vuelta victory completed Team Jumbo-Visma's unprecedented sweep of all three Grand Tours in a single season.