BattleTech: Interstellar Operations is the fifth core rulebook in the BattleTech Total Warfare line. It enables players to scale the action up beyond a single solar system.

Interstellar Operations contains rules for running an entire faction's military as a player tries to conquer numerous solar systems, including rules for how to conduct warfare through scales larger than previously represented within the core line of rulebooks. Finally, perhaps one of the most anticipated portions of the book, the Alternate Eras section introduces a huge swath of rules for playing across the thousand years of Battletech history, including weapons and equipment mostly unique to a given era, such as complete rules for building and playing with LAMs.