<p>This paper explores the cooperative output regulation control of fractional-order multi-agent systems (FOMASs) under external Denial-of-Service (DoS) attacks and internal sensor faults. A distributed resilient observer is constructed to estimate the states of the exosystem. A switching adaptive law is designed to estimate the unmeasurable states of the FOMAS caused by sensor faults, in combination with the output of the sensors. Furthermore, filters and compensation signals are designed to avoid complexity explosion and the need for high-order derivatives of the observer. Based on the aforementioned designs and a backstepping framework, a distributed fault-tolerant control framework is developed, and the stability of the system is proven based on the Lyapunov-stability criterion. The developed control framework can uniformly handle both external DoS attacks and internal sensor faults. Finally, two simulation examples are given to verify the effectiveness of the proposed scheme.</p>