The court ruling Sunday adds that it considers all of the ISIS's affiliates to be terrorist organizations as well.
Ansar Beit al-Maqdis or Champions of Jerusalem, a jihadi group based in the Sinai Peninsula that regularly attacks Egyptian security forces, pledged allegiance to ISIS earlier this month.
ISIS has carved out a self-styled caliphate in territory it controls in Syria and Iraq and demanded the loyalty of the world's Muslims. A U.S.-led coalition is now targeting it in airstrikes.
Other countries across the region also have banned the group.