Beta Group was a group within the fleet of the Rebel Alliance that was led by Commander Lajaie. The group was present at the Mako-Ta Space Docks, where it and other sub-groups were to disperse from the rest of the fleet until it was required to fight against the Galactic Empire.
As the groups were ready to launch into hyperspace, a fault occurred resulting in the ships being unable to launch. Shortly after the launch failure, Death Squadron under the command of Darth Vader arrived. Its flagship was a Mon Calamari Star Cruiser.