Ben Rothwell (born October 17, 1981) is an American mixed martial artist and bare-knuckle boxer who competes as a Heavyweight and is the current BKFC Heavyweight World Champion. He most notably had a 17 bout stint in the Ultimate Fighting Championship and competed for the Quad Cities Silverbacks of the IFL where he held an undefeated 9–0 record before leaving the promotion due to a contract dispute. He has also had one-fight stints in Affliction, M-1 Global, and King of the Cage. He also competed for the World Series of Fighting and Absolute Championship Berkut.

Since his departure from the UFC in 2022, Rothwell has competed in the Heavyweight division of the Bare Knuckle Fighting Championship, where he is the current BKFC Heavyweight Champion. As of October 5th 2025, he is #3 (in BKFC this is actually the 4th ranked fighter) in the men's pound-for-pound rankings.

Rothwell is from Kenosha, Wisconsin, and both of his parents work in the restaurant business. His parents own a catering company. He is of Norwegian and Irish descent. Rothwell was an active child but suffered a bout with spinal meningitis when he was six years old. He was in a coma and temporarily blind, while the disease made him almost obese. The young Rothwell, who struggled with his weight and identity in his adolescent years, was also troubled growing up and was often involved in fighting and violence at Westosha Central High School in Paddock Lake. By the time he was a junior in high school, Rothwell knew that he enjoyed fighting, and in 1999, at the age of 17, he began learning self-defense. In July of that same year, after he had been in three professional fights, he and a friend were involved in a car accident with a drunk driver. Rothwell's friend, who was 19 years old, died two weeks later, and Rothwell suffered a significant head injury, in addition to broken ribs. The event changed Rothwell's life, causing him to feel as though he has a purpose to complete.

Rothwell began his training in September 1999, before joining Miletich Fighting Systems in 2002.

Rothwell made his professional debut in early 2001 in his home state of Wisconsin and dominated his opponent, winning by TKO only 21 seconds into the fight. He then won his next three fights, all under two minutes into the first round and all with strikes. Rothwell then faced future two-time UFC Heavyweight Champion and fellow Miletich Fighting Systems fighter, Tim Sylvia. Rothwell was handed his first career loss in a decision. However, he bounced back and won his next seven fights, all by submission or TKO, before a unanimous decision loss to Mike Whitehead.

After defeating former King of the Cage Super Heavyweight Champion, Dan Bobish by knockout, Rothwell was soon invited to compete in the International Fight League to fight for the Quad City Silverbacks, coached by the legendary Pat Miletich. Like several other fighters in the promotion, Rothwell was competing for the coach who he trained regularly.

On April 29, 2006, Rothwell made his IFL debut against future UFC veteran, the Polish-Canadian fighter, Krzysztof Soszynski. In the first round, Soszynski surprisingly decided to exchange strikes with Rothwell, and landed a left uppercut and held his own until he was knocked down by a short left hook from Rothwell, who then slammed Soszynski to the canvas. After working from side control and then standing again, Rothwell landed a series of punches at the end of the round, that knocked down Soszynski, and then followed this up with more punches to his downed opponent. Despite the round ending, referee Dan Miragliotta called a stop to the contest, granting Rothwell the win via TKO.

After racking up four consecutive IFL wins, he fought future The Ultimate Fighter: Heavyweights winner and IFL Heavyweight Champion Roy Nelson, winning via split decision.