DiffServ networks support three forwarding classes: EF (Expedited Forwarding), AF (Assured Forwarding) and BE (Best Effort). Scheduling algorithms based on priority queueing, such as Priority Queueing with Weighted Round-Robin (PQWRR) are the traditional choices for providing EF service. The Dynamic DiffServ Scheduling (DDS) scheduler can improve the starvation problem for the BE and AF traffics, but scarify the EF performance. This paper proposes an Adaptive Weighted Fair Queueing with Priority (AWFQP) scheduler to provide QoS (Quality of Service) guarantees to EF, AF and BE classes. The objective of the proposed scheduler is to improve the performance of AF and BE classes without scarifying EF performance. Simulation results show that the proposed AWFQP scheduler outperforms the PQWRR and DDS schedulers in guaranteeing QoS (Quality of Service) for the AF and BE classes, improves system throughput and reduces jitter and delay time.