Protesters, who toured the streets of the Jabalia refugee camp, waved placards in support of Hamas and its armed wing.
An Egyptian court on Saturday branded Qassam Brigades a "terrorist organization" after an Egyptian lawyer filed a lawsuit claiming that the brigades were involved in recent attacks against Egyptian army sites in the Sinai Peninsula, which shares borders with the Gaza Strip.
The verdict came two days after scores of people were killed and injured I a spate of militant attacks on security and military sites in the northern quadrant of the Sinai Peninsula.
Senior Hamas member Moshir al-Masry described the Egyptian court ruling as a coup against history."
"It does not reflect the will of the Egyptian people," al-Masry told The Anadolu Agency on the sidelines of the protest.
"This is a politically-motivated ruling," al-Masry said. "It is dangerous and it only seeks to cover up Egypt's security failure in Sinai," he added.
Egyptian security forces have been waging a campaign against militants in Sinai, amid a rise in attacks on army and police personnel since the ouster of elected President Mohamed Morsi in mid-2013.
Egyptian media accuse Hamas, an ideological offshoot of the Muslim Brotherhood, the group from which Morsi hails, of standing behind the violence in Sinai.
The Palestinian faction has, however, repeatedly denied these accusations, saying it cannot act against Egypt's national security.