The complaint was filed on Monday in the U.S. District Court for the Northern District of Ohio by the Cavaliers and its Flash Seats service, which allows people to buy and sell tickets online. It accuses Ticketmaster of anti-competitive practices.
It follows a lawsuit by Ticketmaster against the Cavaliers that was filed earlier this month in the U.S. District Court for the Central District of California.
The Cavaliers said its complaint alleges that Ticketmaster is trying to enforce a contract for direct sale of tickets with the team such that only its services can be used for resale of tickets as well.
Ticketmaster said it had fairly negotiated a contract to serve as both the primary and secondary ticketing company for the Cavaliers.
"However, after accepting a large upfront payment from Ticketmaster for these rights, the Cavaliers breached their contract by establishing a ticketing arrangement with another ticketing company, Flash Seats," Ticketmaster Chief Executive Sean Moriarty said in a statement.