The objective behind this paper is to present a MATLAB Toolbox for elevator simulations; this toolbox is known as 'ElevatorSIM', and it is still under development. ElevatorSIM is based on the GPenSIM, which is software for modeling, simulation, performance analysis, and control of discrete-event systems. In this paper: firstly, the software GPenSIM (General-purpose Petri Net Simulator) is introduced. Secondly, the toolbox ElevatorSIM is presented; the components of ElevatorSIM and some of the functions are also presented. Finally, an application example is given to show the usefulness of the toolbox. The application example compares the performance of two different elevator algorithms. The idea behind the development of ElevatorSIM is to measure the performance of elevators through simulations; for this purpose, steps have been taken to collaborate with a high-tech elevator company. However, this paper - the first paper on ElevatorSIM - is to introduce the existence of the toolbox.