The butterfly sword (Traditional Chinese ; Simplified Chinese: pinyin: húdié shuāng dāo) is a short dāo, or single-edged blade, originally from the South of China, though it has seen use in the North. The blade length is approximately that of the forearm, for easy concealment within the sleeves or inside boots, and for greater maneuverability to spin and rotate in close-quarters fighting.

The butterfly sword is usually wielded in pairs. The sword has also a small crossguard to protect the hands of the wielder, which can be too small to block or hook an opponent's weapon. Butterfly swords are used in several Chinese martial arts, notably Wing Chun, Lau Gar and Hung Gar.

Butterfly swords in fiction

Kano uses a set of butterfly knives in Mortal Kombat: Deadly Alliance

One of the Earth Kingdom pirates, whose job is a barker in the Avatar: The Last Airbender episode The Waterbending Scroll uses a set of butterfly swords. Earthbending, the bending art of the Earth Kingdom, is based on Hung Gar, a martial art where the use of the butterfly swords is extensive.