The judgement comes ahead of an expected verdict on Tuesday against Morsi himself on charges of inciting the killing of protesters in December 2012 when he was president.
The attack in the town of Kerdasa on the outskirts of Cairo on July 3, 2013 came on the same day that then army chief and now President Abdel Fattah al-Sisi announced he was overthrowing Morsi.
Since his ouster, the authorities have cracked down hard on Morsi's Muslim Brotherhood movement with at least 1,400 of his supporters killed.
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Hundreds more have been sentenced to death and thousands jailed, often in speedy mass trials that have been criticised by human rights groups.
Monday's court ruling confirmed the death sentences it handed down against the 22 defendants in March after they had received the statutory approval of the country's highest Muslim religious authority, the mufti.
Fourteen of the 22 defendants are in custody, while eight are on the run, a court official said.
The defendants were convicted of "illegal assembly, vandalism, murder and attempted murder".
Morsi himself is facing five separate trials on charges that carry the death penalty. The verdict in the first of them is expected on Tuesday.