Dou Huaizhen (Chinese: 竇懷貞; died July 29, 713), known by his courtesy name Dou Congyi (竇從一) during the second reign of Emperor Zhongzong (r. 705–710), posthumously renamed Du Huaizhen (毒懷貞), was an official of the Chinese Tang dynasty and Wu Zetian's Zhou dynasty, serving as a chancellor during the reigns of Emperor Ruizong and Emperor Xuanzong.