This paper evaluates the dynamic stability of a hybrid wave and photovoltaic (PV) power generation system integrated into a distribution power grid. The wave power-generation system (WPGS) is simulated by a linear permanent magnet generator driven by an Archimedes wave swing (AWS). The outputs of the WPGS and the PV system are connected to a common dc link through a voltage-source converter (VSC) and a dc/dc boost converter, respectively. The common dc link is interfaced to the distribution power grid via a voltage-source inverter (VSI). A supercapacitor (SC) is utilized to smooth the generated power delivered to the distribution power grid. This paper proposes a control scheme to maintain stable operation of the studied system while achieving maximum power extractions for the wave system and the PV system. Both root-loci analysis of the system eigenvalues under various operating conditions and the time-domain simulation results of the studied system subject to disturbance conditions are presented to demonstrate and verify the effectiveness of the SC combined with the proposed control scheme on performance improvement of the studied hybrid wave and PV system.