Viktor Kadler (born 11 January 1981 in Győr), is a Hungarian sprint canoer.
He won his first major international title in 2004, becoming European champion as a member of Hungary's victorious four-man (K-4) kayak crew in the 200 m final.
In 2005 the Hungarians did the double, retaining their European title and then winning the World Championship final in Zagreb.
In 2006 they lost their 200 m titles, finishing third at the European Championships at Račice, and second at the World Championships in Szeged. The foursome would win gold at the 2007 world championships.
Kadler is a member of the Győri VSE club.