The IEEE 802.16 standard (mobile broadband wireless access system), which is also known as worldwide interoperability for microwave access (WiMAX), is one of the latest technologies in the wireless world. The main goal of WiMAX is to deliver wireless communications with quality of service (QoS) guarantees, security, and mobility. In this article, we have evaluated the performance of the Internet Protocol security (IPSec) over WiMAX networks. We have also illustrated the results of the simulations. We have also depicted the processing time and the throughput introduced when IPSec is applied over WiMAX technology (IEEE 802.16).