Victory Gundam is set in UC 0153 and succeeds the Earth Federation Forcesand Crossbone Vanguard conflict of Gundam F-91. Therefore, it takes place well after the events of the Earth Federation Forces versus Principality of Zeon conflict (which could be said to have ended with Char's Counterattackor Unicorn).
The greatly weakened Earth Federation comes under attack by the BESPA forces of the spaceborne Zanscare Empire; only the AEUG-like League Militaire stands in their way. The mass-produced Victory Gundam is the League Militaire's secret weapon against the invading BESPA.
- gundam.wikia.com