This study explored employees' green brand understanding in realizing green brand citizenship behavior. We propose a model, and data were gathered from 356 Wang Steak's employees in Taiwan. The findings proved the role of green brand understanding on enhancing green brand identification and green brand citizenship behavior. Regarding the effect of green brand identification on green brand love, the finding suggest that green brand identification positively impacts green brand love. In addition, the result identified employees' voluntary green brand behaviors via green brand identification and green brand love.