Tongxiao Township is an urban township in southern Miaoli County, Taiwan. It lies between the Taiwan Strait on the west and mountains on the east.
The town was formerly called Thunsiau ().
The township comprises 24 villages: Baitung, Baixi, Chengbei, Chengnan, Fengshu, Fulong, Fuxing, Fuyuan, Meinan, Nanhe, Neidao, Neihu, Pingan, Pingding, Pingyuan, Tongnan, Tongtung, Tongwan, Tongxi, Wubei, Wumei, Wunan, Xinpu and Zuntou.
The township is part of Miaoli County Constituency I electoral district for Legislative Yuan.
Taiwan High Speed Rail passes through the central part of the township, but no station is currently planned.