This paper establishes mixed duopoly game-theoretical models to investigate the economic impacts exerted by privatization in the presence of the environmental pollution. When the residents’ environmental preference is introduced to the public firm’s objective function, we mainly find that privatization may increase the public firm’s output, decrease the private firms’ outputs, and exert no impacts on social welfare. These findings run contrast to the common findings of the studies on privatization. Moreover, Cournot competition and Stackelberg competition are separately analyzed to show that our findings are robust and irrelevant with the firms’ moves. This paper highlights the role the environmental pollution and residents’ environmental p...