In association football, the formation of a team refers to the position players take in relation to each other on a pitch. As association football is a fluid and fast-moving game, a player's position in a formation does not define their role as tightly as that of rugby player, nor are there breaks in play where the players must line up in formation. A player's position in a formation typically defines whether a player has a mostly defensive or attacking role, and whether they tend to play centrally or towards one side of the pitch.

Association football, commonly known as football, or soccer, is a team sport played between two teams of 11 players each, who primarily use their feet to propel a ball around a rectangular field called a pitch. The objective of the game is to score more goals than the opposing team by moving the ball beyond the goal line into a rectangular-framed goal defended by the opposing team. Traditionally, the game has been played over two 45-minute halves, for a total match time of 90 minutes. With an estimated 250 million players active in over 200 countries and territories, it is the world's most popular sport.