Nikolas Wallenda (born January 24, 1979) is an American acrobat, aerialist, daredevil, high wire artist, and author. He is known for his high-wire performances without a safety net. He holds 11 Guinness World Records for various acrobatic feats, but was best-known as the first person to walk a tightrope stretched directly over Niagara Falls. Wallenda walked 1,800 feet on a steel cable over Masaya Volcano in Nicaragua, his longest walk, on March 4, 2020.

Wallenda is a 7th-generation member of The Flying Wallendas family, and he participated in various circus acts as a child. He made his professional tightrope walking debut at age 13, and he chose high-wire walking as his career in 1998 after joining family members in a seven-person pyramid on the wire. In 2001, he was part of the world's first eight-person high-wire pyramid. He performed with his family at various venues from 2002 to 2005, forming his own troupe in 2005. He performed with Bello Nock in 2007 and 2008 in a double version of the Wheel of Steel that he helped invent. In 2009, he set new personal bests for highest and longest tightrope walks, completing a total of 15 walks above 100 feet (30 m) in the air that year.

In 2008, while performing with Ringling Bros., Wallenda set Guinness World Records for longest and highest bicycle ride on a high-wire 250-foot-long (76 m) at 135 feet (41 m) above the ground in New Jersey. He nearly doubled the height record in 2010 to 260 feet (79 m). On the same day in 2010, he upped his personal best by tightrope walking over 2,000 feet (610 m) in a single performance. He set a world record in 2011 by performing on the Wheel of Death atop the 23 story Tropicana Casino and Resort. Later that year, he and his mother tightrope walked between the two towers of Condado Plaza Hotel in Puerto Rico. The feat was a re-creation of the one that killed Karl Wallenda, Nik's great-grandfather and primary source of inspiration. On June 10, 2011, Wallenda hung from a helicopter 250 feet (76 m) off the ground using only his toes to hold on. Some time after that, he walked on top of a turning Ferris wheel at the Santa Cruz Beach Boardwalk, CA.

Wallenda crossed Niagara Falls on June 15, 2012 on a live ABC special, following a two-year legal battle involving both sides of the Canada–United States border to gain approval. He was required to wear a safety harness for the first time in his life. A reality show aired on the Science Channel which followed his feats. In 2013, he released a memoir entitled Balance. He became the first person to high-wire walk across the Grand Canyon on June 23, 2013. The feat aired live on Discovery breaking rating records for the network. He followed that up with Skyscraper Live, a live Discovery special that aired on November 2, 2014, in which he completed two tightrope walks and set two new Guinness World Records: one for walking the steepest tightrope incline over 600’ up between two skyscrapers, and the other for the highest tightrope walk while blindfolded.

Wallenda is married with three children, and considers his Christian faith to be a central aspect of his life.