Muaythai was added to the World Games following the decision of the IWGA Annual General Meeting in May 2013.

The muaythai competition is organized as a set of tournaments, one for each weight class.

The number of weight classes has changed over the years (currently 3 for men and 3 for women), and the definition of each class has changed several times, as shown in the following table.

From the 2022 World Games, muaythai events achieved full gender equality.

The numbers below are after the 2022 World Games in Birmingham, Alabama, United States.