Systems and methods for synchronizing the playback of network media across multiple content playback devices, termed herein as “playback devices”, “clients”, or “client devices”. In one implementation, client devices are controlled to parse and buffer media content separately. Once all clients are ready, a controller may cause the client devices to start in a synchronized fashion based on signals sent by the controller. The controller adjusts the timing of the signal so that the outputs are displayed in synchronization on each client device. In other implementations, device lag times may be measured. In still other implementations, a master device may synchronize playback of media content on slave devices. In yet other implementations, devices may buffer and join playback of media content occurring on other devices. In further implementations, the systems and methods may be expanded to include steps of processing authentication for service providers prior to arranging synchronized playback.