David Lee "Tank" Abbott (born April 26, 1963 in Huntington Beach, California) is an American mixed martial arts fighter. He has described his fighting style, which he developed brawling in the bars and streets of Huntington Beach, California, as "Pit Fighting." In addition to his MMA career, Abbott wrestled professionally between 1999 and 2001 under the ring name Tank Abbott.

Abbott was a frequent participant in the Ultimate Fighting Championship (UFC). As of 2007 he had a record of 8-10 in that promotion. Abbott made his Mixed Martial Arts (MMA) debut in 1995 at UFC 6 Clash of the Titans in Casper, Wyoming. In his opening fight, he knocked out John Matua, who weighed 400 lb, in 18 seconds. Later that night he fought Oleg Taktarov for over 17 minutes before succumbing to a rear naked choke. Both men collapsed in exhaustion after the fight, and Taktarov had to be carried out of the cage.

Despite never winning a UFC title, Abbott achieved a large amount of popularity due in large part to his displays of power and aggression and his no-nonsense, often comically disrespectful attitude. He also gained a degree of notoriety for his unorthodox look and fighting style, more reminiscent of a street fighter than a martial artist.

As of December 2008, Abbott has lost 8 of his last 9 fights, the most recent of which was a first round knockout loss to Kimbo Slice in February 2008, at Elite XC's Street Certified event.

His most recent fight was against Mike Bourke on February 13th, 2009 at The Selland Arena in Fresno, California as a part of the Valentine's Eve Massacre Event. Abbott knocked out Bourke in the first round and secured a victory for the first time in nearly four years. UFC Hall of Famer and fellow MMA legend, Ken Shamrock and Abbott have separately acknowledged that they are currently inking the contract to fight each other in April of this year.

Abbott has recently confirmed to "The Savage Dog Show" on Sherdog radio, that he has finished writing his book "Before There Were Rules", which chronicles his life, times and exploits in Huntington Beach prior and leading to his arrival at the UFC.