Jiànzi (毽子), ti jiànzi (踢毽子), ti jian (踢毽) or jiànqiú (毽球) is a traditional Asian game in which players aim to keep a heavily weighted shuttlecock in the air using their feet and other parts of the body (but not hands, unlike the similar games peteca and indiaca). The game, which goes by many different names (see below), may be rules-based on a court similar to badminton and Volleyball, or be played artistically, among a circle of players in a street or park, with the objective to keep the shuttle 'up' and show off skills. In Vietnam, it is known as đá cầu and is the national sport, played especially in Hanoi.

In recent years, the game has gained a formal following in Europe, the United States and elsewhere.

In English, both the sport and the object with which it is played are referred to as "shuttlecock" or "featherball". No racquets are used.

The shuttlecock, called a jianzi in the Chinese game and also known in English as a 'Chinese hacky sack' or 'kinja', typically has four feathers fixed into a rubber sole or plastic discs. Some handmade jianzis make use of a washer or a coin with a hole in the center.