Alexander J Honnold (born August 17, 1985) is an American rock climber best known for his free solo ascents of big wall climbing routes. Honnold rose to worldwide fame in June 2017 when he became the first person to free solo a full route on El Capitan in Yosemite National Park via the 880-metre (2,900 ft) route Freerider at grade 5.13a, the first-ever big-wall free-solo ascent at that grade, a climb described in The New York Times as "one of the great athletic feats of any kind, ever".

In 2015, he won a Piolet d'Or in alpine climbing with Tommy Caldwell for their completion of the enchainment (known as the Fitz Traverse) of the Cerro Chaltén Group (or Fitzroy Group) in Patagonia over five days. On January 25, 2026, he free soloed the Taipei 101 tower in Taipei, Taiwan, the tallest buildering free solo climb in history and graded at circa. 5.11.

Honnold is the author (with David Roberts) of the memoir Alone on the Wall (2015) and the subject of the 2018 biographical documentary Free Solo, which won an Academy Award and a BAFTA.

Honnold was born on August 17, 1985, in Sacramento, California. His mother, Dierdre Wolownick (b. 1951), is a community college professor.. His father was Charles Honnold (1949–2004). His paternal roots are German, and his maternal roots are Polish. He started climbing in a climbing gym at the age of 5 and was climbing "many times a week" by age 10. He participated in many national and international youth climbing championships as a teenager.

"I was never, like, a bad climber [as a kid], but I had never been a great climber, either," he says. "There were a lot of other climbers who were much, much stronger than me, who started as kids and were, like, instantly freakishly strong – like they just have a natural gift. And that was never me. I just loved climbing, and I've been climbing all the time ever since, so I've naturally gotten better at it, but I've never been gifted."

After graduating from Mira Loma High School as part of the International Baccalaureate Programme in 2003, he enrolled at the University of California, Berkeley, to study civil engineering. His maternal grandfather died, his parents divorced during his first year of college, and Honnold skipped many of his classes to boulder by himself at Indian Rock.

Honnold dropped out of Berkeley and spent time living at home and driving around California to go climbing. "I'd wound up with my mom's old minivan, and that was my base," he said. "I'd use it to drive to Joshua Tree to climb or I'd drive to LA to see my girlfriend. I destroyed that van fairly quickly; it died on me one day, and for the next year, I lived just on my bicycle and in a tent."

In 2007, he bought a 2002 Ford Econoline E150 van, which allowed him to focus on climbing and following the weather.