Safety (S), historically known as a safetyman, is a position in gridiron football on the defense. The safeties are defensive backs who line up ten to fifteen yards from the line of scrimmage. There are two variations of the position: the free safety (FS) and the strong safety (SS). Their duties depend on the defensive scheme. The defensive responsibilities of the safety and cornerback usually involve pass coverage towards the middle and sidelines of the field. While American (11-player) formations generally use two safeties, Canadian (12-player) formations generally have one safety and two defensive halfbacks, a position not used in the American game.

In American football, the specific role that a player takes on the field is referred to as their "position". Under the modern rules of American football, both teams are allowed 11 players on the field at one time and have "unlimited free substitutions", meaning that they may change any number of players during any "dead ball" situation. This has resulted in the development of three task-specific "platoons" of players within any single team: the offense, the defense, and "special teams". Within these three separate "platoons", various positions exist depending on the jobs that the players are doing.