Dadao, formerly romanized ta-tao, may refer to:

• dadao (大刀, p dàdāo, lit. 'big knife'), a machete-like variety of the dao (sword)
  • "The Sword March", a Chinese song during the Second Sino-Japanese War (World War II) which begins Dadao!
• Tao, the "Great Way" (大道, p Dàdào) of Eastern philosophy
  • The Great Way Government of Shanghai (1937–38) during the early stages of the Second Sino-Japanese War (World War II)