Halo 5

343 Industries general manager Bonnie Ross recalled that after Halo 4, the team spent a lot of time discussing where they wanted to take the Halo series, reflecting on feedback from fans about what they did and did not like. In late 2012, Tim Longo, David Berger, and Chris Lee laid out the studio's vision for the next game from a creative and technical standpoint, setting key goals to focus on: utilizing the Xbox One's hardware and Microsoft's cloud infrastructure for larger campaign and multiplayer spaces, deeper player investment systems, and a frame rate of 60 frames per second (FPS).

At Electronic Entertainment Expo 2013 (E3), Microsoft announced a new, then-untitled addition to the Halo series, along with a trailer appearing to depict a post-Halo 4 Master Chief. After E3, Phil Spencer said the "Reclaimer Trilogy" had been expanded into a longer series of games, explaining that the developers "[didn't] want to limit the Reclaimer story within a trilogy." Ross confirmed the game's title and 2015 release date in a May 2014 blog post. The game is exclusive to the Xbox One.

Halo: The Master Chief Collection gave players exclusive access to the Halo 5: Guardians multiplayer beta, which began December 29, 2014, and ran through January 18, 2015. In response to the negative coverage of The Master Chief Collection's broken launch, O'Connor announced that Guardians would not be broken at launch.