Warhammer 40,000: Battlesector is a turn-based tactics video game developed by Black Lab Games and published by Slitherine Software for Windows on July 15, 2021. It is based on Games Workshop's tabletop wargame Warhammer 40,000.

Slitherine Software UK Limited is a British video game developer and publisher founded on 25 June 2000. It is responsible for the production of a range of over 200 strategy and war video games. Slitherine developed and/or published a number of licensed games with brands including Battlestar Galactica, Warhammer 40,000, Starship Troopers, Horrible Histories and The History Channel. It also produces rules for a series of tabletop wargames called Field of Glory.