Hao or HAO may refer to:

  • Hào, a form of Chinese pseudonym
  • Hao (Chinese surname) (郝), a Chinese surname
  • Hao (French Polynesia)
  • Hao (city), (镐/鎬, an abbreviation for the city of Xi'an, Shaanxi (China)
  • Haojing, (镐京/鎬京) ancient capital of the Zhou Dynasty which stood on the spot of present day Xian
  • Hao Mengling, Chinese general
  • Hao Asakura, a character in Shaman King media
  • Hao Si-wen, a character in the Water Margin universe
  • Hsu Hao, a character in Mortal Kombat media
  • HAO or High Altitude Observatory
  • HA0, a postcode area of the United Kingdom
  • Hao of Oahu, Prince of Oahu
  • Heather O'Reilly, Heather Ann O'Reilly, American soccer player.
  • Rauvolfia sandwicensis, a plant endemic to Hawaii