This paper deals with the three-dimensional computer simulation of the weft insertion process as a possible solution to avoid costly weaving trials when researching this process. A three-dimensional mathematical model of the yarn was developed, in which the behavior of the yarn was described by the Second Law of Newton. For this mathematical model, a second order differential equation needed to be solved. To this end, an explicit integration using Euler’s method was chosen. In order to validate the model, high-speed camera recordings were performed on a test stand and compared with simulations of the same test stand. A very good resemblance was found between simulation and camera recordings. This is the first time that a three-dimensional model for the weft insertion on air-jet looms has been successfully tested.