Most, if not all, computerized adaptive testing (CAT) programs use simulation techniques to develop and evaluate CAT program administration and operations, but such simulation tools are rarely available to the public. Up to now, several software tools have been available to conduct CAT simulations for research purposes; however, these existing tools, for the most part, oversimplify the CAT algorithms and are not powerful enough to simulate operational CAT environments. SimulCAT, a new CAT simulation software tool, was developed to serve various purposes ranging from fundamental CAT research to technical CAT program evaluations. The new CAT simulation software tool offers many advantages, including a wide range of item-selection algorithms, adaptability for a variety of CAT administration environments, and a user-friendly graphical interface, among others, as described in this commentary.