Summary: The problem of event-triggered output feedback control for networked control systems (NCSs) with packet losses and quantization is addressed. A new dynamic quantization scheme is proposed to prevent saturation of the quantizer in the presence of external disturbances, and using the emulation-based approach, we show how to design the event-triggering conditions to guarantee the \(L_2\)-gain performance of the overall system. To cope with the successive packet losses and the dynamic quantization, the NCS is embedded into a hybrid dynamical system, which is capable of describing these dynamics. Then, a novel Lyapunov function type is constructed to analyze the \(L_2\)-gain performance with the quantization and packet dropout effects. Furthermore, owing to the proposed method, the Zeno phenomenon resulting from the transmission instants and updates of quantizer are prevented by introducing a minimum inter-event time. Finally, a numerical simulation is introduced to demonstrate the feasibility of the proposed design approach.