Cai E (simplified Chinese: ??; traditional Chinese: ??; pinyin: Cà i È; Wade–Giles: Ts'ai4 O4; 18 December 1882 – 8 November 1916) was a Chinese revolutionary leader.
He was born Cai Genyin (Chinese: ???; pinyin: CÃ i GenyÃn) in Shaoyang, Hunan, and his courtesy name was Songpo (Chinese: ??; pinyin: Songpo).
Cai eventually became an influential warlord in Yunnan, and is best known for his role in challenging the imperial ambitions of Yuan Shikai during the anti-monarchy war.
Cai's name has also been romanised as Tsai Ao.