Court spokesman Sofiane Selliti said the organisation violated laws governing associations, and that its headquarters and 20 branches will be shut down.
Formed in 2012, the group's goal was to seek out members of the old regime and protect the gains of the revolution. It was seen as close to the Islamist Ennahda Party that dominated elections.
Opposition parties, however, accused the league of attacking rival party rallies and intimidating opponents.
They also accused it of being behind the death of an opposition politician in Tattouine in 2012.