A cartridge locking mechanism for a tape player having a tunnel for receiving a tape cartridge, comprises a pivotally mounted arm having a projection extending into the tunnel in the path of a cartridge received therein. A torsion spring mounted for rotational and torsional movement adjacent the tunnel includes a first end extending outwardly therefrom for engagement with the actuator arm. The second end of the spring extends outwardly toward the cartridge receiving tunnel and includes a roller for receipt in a groove in a side wall of the cartridge. When inserted into the tunnel, the cartridge engages the projection, causing the actuator arm to rotate. Rotation of the arm in turn rotates the torsion spring, thereby to move the roller into the tunnel in engagement with the cartridge in the groove therein. Full insertion of the cartridge into the tunnel ''''twists'''' the torsion spring, providing a force at the roller directed against the tape cartridge to maintain the latter secured in the tunnel.