Futsal (also known as fútsal or footsal) is a ball sport played on a hard court, smaller than a football pitch, and mainly indoors. It has similarities to five-a-side football.

Futsal is played between two teams of five players each, one of whom is the goalkeeper. Unlimited substitutions are permitted. Unlike some other forms of indoor football, the game is played on a hard court surface delimited by lines; walls or boards are not used. Futsal is also played with a smaller, harder, low-bounce ball. The surface, ball and rules together favour ball control and passing in small spaces. The games “emphasis is on improvisation, creativity and technique”.

室内五人制足球（Futsal）或又稱為室內足球，是國際足總正式認可的足球比賽型式，名字取自葡萄牙語futebol de salão及西班牙語fútbol sala或fútbol de salón，意思是「房間足球」。

室內五人制足球由兩隊對賽，每隊五人中一人為守門員；此外各隊可以有數位後備球員。與其他形式的室內足球比較，futsal的場地以畫線為界，而非皮球可以回彈的網或板。

其他的室內足球有不同的規則，名稱有indoor football，five-a-side football（五人足球）或indoor soccer。這些形式在室內足球正式訂立規則前已出現。