The nunchaku (/nʌnˈtʃækuː/) (Japanese: ヌンチャク, sometimes dual-section stick, nunchuks (/ˈnʌntʃʌks/), nunchucks, chainsticks, or chuka sticks in English)[a] is a traditional East-Asian martial arts weapon consisting of two sticks (traditionally made of wood), connected to each other at their ends by a short metal chain or a rope. It is approximately 30 cm or 12 inches (sticks) and 2.5 cm or 1 inch (rope). A person who has practiced using this weapon is referred to in Japanese as nunchakuka (ヌンチャク家, nunchakuka).

NunchakuBruce Lee performs nunchakuThe nunchaku is most widely used in Southern Chinese Kung fu, Okinawan Kobudo and karate. It is intended to be used as a training weapon, since practicing with it enables the development of quick hand movements and improves posture. Modern nunchaku may be made of metal, plastic, or fiberglass instead of the traditional wood. Toy versions and replicas not intended to be used as weapons may be made of polystyrene foam or plastic. Possession of this weapon is illegal in some countries, except for use in professional martial arts schools.

The origin of the nunchaku is unclear. One traditional explanation holds that it was originally invented by Emperor Taizu of Song, as a weapon utilised in war, initially named Grand Ancestor Coiling Dragon Staff (大小盤龍棍/太祖盤龍棍, taai3 zo2 pun4 lung4 gwan3/taai3 zo2 pun4 lung4 gwan3). Another weapon, called the tabak-toyok, native to the northern Philippines, is constructed very similarly, suggesting that it and the nunchaku descended from the same instrument.

In modern times, the nunchaku and the tabak-toyok were popularized by the actor and martial artist Bruce Lee and by Dan Inosanto. Lee famously used nunchaku in several scenes in the 1972 film Fist of Fury. When Tadashi Yamashita worked with Bruce Lee on the 1973 film Enter the Dragon, he enabled Lee to further explore the use of the nunchaku and other kobudo disciplines. The nunchaku is also the signature weapon of the character Michelangelo in the Teenage Mutant Ninja Turtles franchise.