Fortnite Battle Royale is a free-to-play battle royale online video game developed and published by Epic Games. It is a companion game to Fortnite: Save the World, a cooperative survival game with construction elements. It was initially released in early access on September 26, 2017, for Microsoft Windows, macOS, PlayStation 4, and Xbox One, followed by ports for iOS, Android, and the Nintendo Switch the following year.

The concept of the game is similar to previous games of the genre: 100 players skydive onto an island and scavenge for gear to defend themselves from other players. Players can fight alone (Solo), with one additional player (Duos), or with a group of up to three others (Squads). As the match progresses, the playable area within the island gradually constricts, giving the players less and less room to work with. The last player or team alive wins the match. The main distinction from others in the genre is the game's construction elements, which can give advantages based on skill level and utilization. Battle Royale uses a seasonal approach with battle passes to introduce new character customization content in the game, as well as limited time events, some of which correspond with changes to the game map. Since its initial release, several other game modes have been introduced, including "Playground", which somewhat serves as a training mode.

The idea for Battle Royale arose following the release of PlayerUnknown's Battlegrounds, a similar battle royale game that was highly successful, but was noted for its technical flaws. Originally released as part of the early access version of Save the World, Epic later transitioned the game to a free-to-play model funded by microtransactions. Following its rise in popularity, Epic split the development team, with one focusing on Battle Royale and the other on Save the World.

Battle Royale received positive reviews from critics, who praised its learning curve, gameplay, art style, and progression system, but noted its similarity to previous games in the genre. The game quickly rose in popularity following its release, eventually surpassing Battlegrounds in overall player count and revenue. By March 2019, the game had been played by over 250 million people and had generated over 2 billion dollars worldwide. The game has gone on to become a cultural phenomenon, with promotion through social media and several celebrities, including Ninja, Marshmello, and Drake, contributing to the game's popularity, achieving record high viewerships on streaming websites in the process.