Zen Do Kai is a freestyle martial art system which was developed in Australia in 1970 by Bob Jones. The style was founded by Jones and Richard Norton when they left the Japanese Goju Kai karate dojo of Tino Ceberano. Jones opened his first Zen Do Kai martial arts club at 48 Elizabeth Street, Melbourne. It was originally intended to cater for those who worked in the security industry with Jones. It is a martial arts system which has evolved over the past three decades. Zen Do Kai is a simplified street fighting art with clubs located across the whole of Australia and New Zealand; and affiliates based in most major cities; as well as schools in Israel, Japan, Indonesia and the USA. It became the largest Martial Arts organisation in Australasia, with nearly 1000 classes per week. Jones describes Zen Do Kai is an "open system", and as such is "open to influences and ideas from all around the world".

Zen Do Kai means - "the best of everything in progression". Its elements include self defence moves, katas, and strike work. Although Zen Do Kai is considered a form of karate, it also contains elements of Thai kickboxing in that each student is taught to fight in a Thai kickboxing stance and to use all of its techniques. It is set apart from many forms of karate because it allows kicks to the legs to take place during sparring and pad drills as well as many other techniques and practices used by Thai kickboxing.

The Zen Do Kai philosophy encompasses the principle of "if it works, use it" and as such contains eleements of a variety of other martial arts including Brazilian Jiu Jitsu, Judo, Aikido, the Filipino martial arts and many more.

Zen Do Kai uses katas as a form of discipline during training and these katas have been selected for the aid in rudimentary development of stances and techniques. Zen Do Kai also places a large emphasis on grabs and holds and other general close combat and ground fighting techniques which may make Zen Do Kai very well suited to practical defence situations. While it would be equally useful in streetfighting, Zen Do Kai follows the classical martial arts model with a distinct hierarchy, a philosophy and the promotion of the ethical code of bushido. Zen Do Kai schools place an emphasis on self defence but do not promote fighting or violence.