Antoni Barend Hardonk (born February 5, 1976) is a retired Dutch mixed martial artist and kickboxer who competed in K-1 and the UFC.
Antoni made his K-1 debut at the K-1 World Grand Prix 2001 Preliminary Scandinavia on June 9, 2001 where he was participating in an eight-man elimination tournament. He faced Swede Fredic Rosenberg in the quarter finals and quickly defeated him via technical knockout in the first round. In the semi finals he faced another Swede, Wisam Feyli, who he defeated by a third round unanimous decision, thus booking his place in the tournament final. In the final match Antoni faced yet another Swede, Larry Lindwall, but was unable to win the tournament, losing instead by second round technical knockout.
On September 29, 2002 Antoni would face fellow Dutch kickboxer and future K-1 Grand Prix Champion Remy Bonjasky at the It's Showtime – As Usual / Battle Time event in the Netherlands. Antoni held his own during the fight but eventually lost via a fifth round unanimous decision. He would lose his next couple of fights against Attila Karacs and Badr Hari respectively before ending a four fight losing streak on July 29, 2005, by defeating Croatian Domagoj Ostojic by third round technical knockout at Ultimate Nokaut 2.