The Nam Hao (Thai: น้ำฮาว, in Thai pronounced as /náːm hāːw/) or Huai Nam Hao (Thai: ห้วยน้ำฮาว) is a watercourse of Thailand. It is a tributary of the Nan River, which it joins near Ban Aham in Nan Province.
An ancient castle moat in Nantong, China is also referred to as the Hao River.