Indoor soccer or arena soccer is a five-a-side or six-a-side version of minifootball, derived from association football and adapted to be played in walled hardcourt indoor arena. Indoor soccer, as it is most often known in the United States and Canada, was originally developed in these two countries as a way to play soccer during the winter months, when snow would make outdoor play difficult. In those countries, gymnasiums are adapted for indoor soccer play. In other countries the game is played in either indoor or outdoor arenas surrounded by walls, and is referred to by different names.

Five-a-side football is a version of minifootball, in which each team fields five players. Other differences from association football include a smaller pitch, smaller goals, and a reduced game duration. Matches are played indoors, or outdoors on artificial grass pitches that may be enclosed within a barrier or "cage" to prevent the ball from leaving the playing area and keep the game constantly flowing.