Zhang Jiazhen (張嘉貞; 666 – September 19, 729), formally Marquess Gongsu of Hedong (河東恭肅侯), was a Chinese military general and politician. He was an official serving under Wu Zetian's Zhou Dynasty and served as a chancellor during the reign of Emperor Xuanzong of Tang. During Emperor Xuanzong's reign, he also served as a general. He was known for being capable but also being self-important during his term as chancellor.