Antoni Hardonk (born February 5, 1976) is a Dutch mixed martial arts fighter and kickboxer who has competed in K-1 and the UFC.

Antoni made his UFC debut at UFC 65 - Bad Intentions on November 18, 2006, defeating Sherman Pandergarst by technical knockout due to leg kicks.

His next fight was at UFC Fight Night 9 on April 5, 2007 against Justin McCully, a late-notice replacement for Hardonk's original opponent, former UFC Heavyweight champion Frank Mir, as he had to drop out due to a shoulder injury. Hardonk lost to McCully via unanimous decision.

Hardonk's next fight was against Frank Mir at UFC 74 on August 25, 2007. Hardonk lost due to a kimura lock early in the first round. Most recently, Antoni beat Colin Robinson at UFC 80 by TKO 17 seconds into the first round and Eddie Sanchez at UFC 85 by TKO in the second round. Hardonk returned to the Octagon on December 27, at UFC 92 where he defeated newcomer, Mike Wessel via 2nd round TKO.