An Egyptian court on Monday sentenced Alaa Abdel Fattah, a leading dissident in the 2011 uprising that toppled strongman Hosni Mubarak, to five years in prison over an illegal protest.
The remaining 24 defendants in the case received sentences ranging from three to 15 years.
The defendants in the caged dock mockingly applauded when the judge pronounced the verdict, as relatives and supporters in the courtroom chanted: "Down with military rule".
Once described by the authorities as an "icon of the revolution" of 2011, Abdel Fattah had initially been sentenced to 15 years in jail but a court ordered a retrial.
The 32-year-old was among dissidents arrested after a November 2013 protest outside parliament in defiance of a law that banned all demonstrations except those authorised by police.
Three defendants were sentenced to 15 years because they were not present in the court. Another received five years and the rest three. All were fined 100,000 pounds (about $13,000).
The dissidents had been accused of assaulting police, but it was unclear if the charge was included in Monday's ruling.
"It's the last act in the circus," Abdel Fattah's sister Mona Seif wrote on Twitter. Another sister, Sanaa, was also jailed for protesting in a separate trial.
The case was among the most prominent in a series of trials of secular dissidents who have been jailed along with thousands of Islamists since the army overthrew Islamist president Mohamed Morsi in July 2013.
The former army chief and now President Abdel Fattah al-Sisi had said on Sunday that he would soon free "youths" wrongfully detained in the crackdown.
"These are the innocent youths Sisi spoke about in his address yesterday," Khaled Dawud, a leader of the liberal Constitution party, said after Monday's verdict. Two of the defendants are party members.
"It is a shame for a country that witnessed two revolutions to imprison youths for protesting," he said.
Some of the defendants, including Abdel Fattah, had supported the Islamist's overthrow but turned against the new government as it expanded its crackdown.
More than 1,000 people, mostly Islamists, have been killed in protest clashes since, while militant attacks have left dead scores of policemen and soldiers.
"Sisi put the youths who placed him in the (presidential) chair in jail," said the mother of one of the defendants.
Ahmed Maher, a leader of the April 6 movement which spearheaded the revolt against Mubarak, had also been sentenced to three years in prison on similar charges.
The revolt against Mubarak erupted on January 25, 2011, with hundreds of thousands of protesters taking to the streets across Egypt for 18 days until he stepped down.
Despite their role in the popular uprising, the secular dissidents have little backing in a country buffeted by turmoil since Mubarak's overthrow.
Many Egyptians who voted for Sisi in the May 2014 election say the country needs a firm hand to restore stability and the economy.
The former field marshal is also widely supported in Egyptian media, which has often tarred his Islamist opposition as terrorists and secular dissidents as rabble rousers.
A court has even banned the April 6 group.
But jailing dissidents such as Abdel Fattah also conflicts with Sisi's message that his popularly backed ousting of Morsi was no different than the 2011 democratic uprising, rather than a counter revolution.