Jan Plas (16 March 1945 – 1 September 2010) was a Dutch professional kickboxer, trainer and founder of the Mejiro Gym in Amsterdam.

Plas began his career in martial arts in karate, learning Kyokushin from Jon Bluming.

He also went on to run the Vos Gym and trained many world-class fighters including Lucien Carbin, Rob Kaman, Fred Royers, Andre Mannaart, Ivan Hippolyte, Ernesto Hoost and Peter Aerts.

In 1986, he was involved in the kidnapping of Gijs van Dam II, the son of hash dealer Gijs van Dam, with a gang run by the drug lord Johan Verhoek, also known as "De Hakkelaar".

[4] In April 2008, Plas was arrested on suspicion of drug trafficking and his daughter and son-in-law, both police officers in Amsterdam, were charged with fraud and money laundering.