Nanzhuang Township is a rural township in Miaoli County, Taiwan.
It has a population total of 9,029 (January 2023) and an area of .
The population consists of Hakkas, Hoklos and the indigenous Saisiyat and Atayal people.
The township comprises nine villages: Nanfu, Nanjiang, Penglai, Shishan, Tianmei, Tung, Tunghe, Xi and Yuanlin.
The township is part of Miaoli County Constituency II electoral district for Legislative Yuan.