Jonathan Siegrist (born 27 August, 1985) is an American rock climber who is regarded as one of the world's most prolific extreme sport climbers, and who has redpointed, and made numerous first free ascents, of a large number of sport climbing routes at and above the grade of 9a (5.14d).

[1] While principally known as a sport climber, he has repeated some of the world's hardest traditional climbing routes.

[9] Over the following year, Siegrist became only the fifth person in history to complete the "9a+ Trilogy",[2][a] adding La Rambla, and Papichulo.

[10] In 2017, Siegrist cemented his status at the 9a+ grade, with ascents of Pachamama, Joe Mama and Chaxi, all completed in one six-week trip to the famous Oliana crag in Spain.

[6] In 2016, Siegrist made the first repeat of Tommy Caldwell's 2013 route, Direct Dunn-Westbay (5.14a/b), belayed by his 66-year-old father, Bob.