No Man's Sky is an exploration survival game developed and published by Hello Games. It was released worldwide for the PlayStation 4 and Microsoft Windows in August 2016, for Xbox One in July 2018, and for the PlayStation 5 and Xbox Series X and Series S consoles in November 2020. The game is built around four pillars: exploration, survival, combat, and trading. Players are free to perform within the entirety of a procedurally generated deterministic open world universe, which includes over 18 quintillion planets. Through the game's procedural generation system, planets have their own ecosystems with unique forms of flora and fauna, and various sentient alien species may engage the player in combat or trade within planetary systems. Players advance in the game by mining for resources to power and improve their equipment, buying and selling resources using credits earned by documenting flora and fauna, or otherwise seeking out the mystery around the Atlas, an entity at the center of the galaxy which serves the game's overarching plot (see § Plot).

Sean Murray, the founder of Hello Games, had wanted to create a game that captured the sense of exploration and optimism of science fiction writings and art of the 1970s and 1980s with No Man's Sky. The game was developed over three years by a small team at Hello Games with promotional and publishing help from Sony Interactive Entertainment. The game was seen as an ambitious project for a small team by the gaming media, and Murray and Hello Games drew significant attention leading to its release.

No Man's Sky received mixed reviews at its 2016 launch, with some critics praising the technical achievements of the procedurally generated universe, while others considered the gameplay lackluster and repetitive. However, the critical response was marred by the lack of several features that had been reported to be in the game, particularly multiplayer capabilities, though Murray had tried to downplay expectations prior to release. The game was further criticised due to Hello Games' lack of communication in the months following the launch, creating a hostile backlash from some of its player base. Murray stated later that Hello Games had failed to control the exaggerated expectations of the game from the media and the larger-than-expected player count at launch, and since have taken an approach of remaining quiet about updates to the game until they are nearly ready to ship to avoid miscommunication. The promotion and marketing for No Man's Sky became a subject of debate, and the video game industry has used it as an example of missteps to avoid in marketing.

Since the game's initial release, Hello Games has continued to improve and expand No Man's Sky to achieve the vision of the experience they wanted to build. The game has received multiple major content updates that have introduced several previously missing features, such as multiplayer components, while adding new features like surface vehicles, base-building, space fleet management, cross-platform play, and virtual reality support, all of which have substantially improved its overall reception.