Due to the fact that the wireless links in an ad hoc network are susceptible to attacks and the nodal mobility renders the network to have a highly dynamic topology, it becomes critical to detect major attacks against the routing protocols of such networks and also provide some extent of QoS to the network traffic. In this paper, we present a new secure routing protocol (SRP) with quality of service (QoS) support, called trustworthiness-based quality of service (TQOS) routing, which includes secure route discovery, secure route setup, and trustworthiness-based QoS routing metrics. The routing control messages are secured by using both public and shared keys, which can be generated on-demand and maintained dynamically. The message exchanging mechanism also provides a way to detect attacks against routing protocols, particularly the most difficult internal attacks. The routing metrics are obtained by combing the requirements on the trustworthiness of the nodes in the network and the QoS of the links along a route. The simulation results have demonstrated the effectiveness of the proposed secure QoS routing protocol in both security and performance.