Five Nights at Freddy's is an American media franchise created by Scott Cawthon, which began with the eponymous 2014 video game and quickly became a worldwide pop-culture phenomenon. The success of the video games led to the publication of several books, including a novel trilogy, a guide book, an activity book, and an anthology series. A film adaptation is also planned. Merchandise for the games has been produced, and a horror attraction based on the series was featured in the Adventuredome for Halloween 2016. The series appeared in the Guinness Book of Records: Gamer's Edition, setting a record for the largest number of sequels released in a year.

The main series consists of nine games. In the first three games, the player controls a nighttime security guard who must utilize security cameras and other tools to survive against animatronic characters which become mobile and homicidal after-hours. The fourth game takes place in the house of a child who must defend against nightmarish versions of the animatronics. The fifth game is set in a maintenance facility owned by a sister company of Freddy Fazbear's Pizza, where the player character is a technician who must complete different tasks each night. In the sixth game, the player assumes the role of a new owner of the pizzeria. The seventh game allows the player to alter the difficulty settings of fifty antagonists from the previous games. The eighth game features virtual reality gameplay. The ninth game features augmented reality gameplay. The tenth game will feature a modernized shopping mall.

To progress through the games, the player must guard themselves against animatronics with a variety of tools. In Five Nights at Freddy’s, the player can control the two security doors connecting their office to the adjacent hallways as a barrier against animatronics in the vicinity. Each night, the player has a power supply that depletes faster when a tool is used. Five Nights at Freddy's 2 has different tools; the protective doors are absent, and the player must instead use an empty Freddy head and flashlight to defend themselves against the animatronics. The game introduced a music box that must be remotely wound up on a regular basis to prevent an attack by a particular animatronic. 8-bit minigames were introduced, which can be played randomly after death.

Five Nights at Freddy's 3 uses a monitor panel, which contains audio, camera, and ventilation. The player must keep certain systems from malfunctioning. These malfunctions can be triggered randomly or by the hallucinations of past iterations of the animatronics. The ability to seal vents is also added and must be used to prevent the sole tangible animatronic from entering the office. The player can use an audio-based function on the cameras, which triggers a childlike voice to lure the animatronic away from the office. The 8-bit minigames return and are activated by completing side tasks such as clicking on a poster or inputting a code into a wall. If the player completes the minigames, they unlock a secret ending. In Five Nights at Freddy's 4, the gameplay occurs in a bedroom set, and instead of being a nightguard, the player takes the role of a small child. The player also no longer has access to a camera system. The player has four areas in the bedroom to monitor: two hallway doors on both sides of the room, the closet directly in front of them, and the bed behind them. The player must listen to the animatronics' breathing, which can determine whether they are near. If the player hears breathing at the side doors, they close the door and wait for the animatronics to walk away. If they close the doors too early, however, the animatronics jumpscare the player when the door is opened. Five Nights at Freddy's 4 introduces a new minigame involving a new animatronic, Plushtrap, which offers the player a two-hour skip the next night for completing the minigame.

An elevated control pad is introduced for Sister Location, which can light a room or shock the animatronics. Other mechanics include a second control pad in the breaker room which controls power to the facility and a flash beacon, which allows the player to see in the dark Funtime Auditorium and avoid its animatronic. Sister Location is the only game where the player can move between rooms. Freddy Fazbear's Pizzeria Simulator has business-style gameplay, and the player must spend in-game money to buy features for the pizzeria. A series of minigames can be played by testing the establishment's attractions. After the player has completed this portion of the game, they complete tasks in a room and fend off hostile, previously-salvaged animatronics. The gameplay of Freddy Fazbear's Pizzeria Simulator shares a number of elements with Five Nights at Freddy's 3, including the importance of ventilation and the ability to distract the animatronics with sound. Ultimate Custom Night is a customizable night, in which fifty animatronics are present and have a maximum AI level of twenty. The game includes many mechanics from the previous games, such as the heater, fan, music box, and power generator.