The WiMAX system outlines support for quality of service (QoS) through several service classes differentiation. However, no specific scheduling has been defined to carry the task. In this paper, we propose a simple and standard-compliant scheduling algorithm for downlink and uplink connections. The proposed algorithm calculates and grants the needed resources in terms of slots based on the QoS requirements and the priority of the service classes. The simulation results show that the scheduling algorithm has fulfilled the QoS provisions of all service classes of WiMAX system in terms of delay and throughput requirements.