Twenty people received a two-year suspended prison sentence for their part in a deadly attack on the US embassy in Tunisia last year, their lawyer said.
The verdict, which was not made public, came after only half a day - an unusually short trial in the north African country.
"We will see if their families want to appeal. If so, we will do it," lawyer Anouar Ouled Ali said.
Hundreds of Islamist protesters attacked the US mission in Tunis on September 14 after an American-made film mocking their religion was published on the internet.
Four of the protesters were killed and dozens wounded in the violence, which saw the mob storm the embassy and torch a neighbouring American school.
Questioned individually by the judge, the accused denied taking part in the protest or attacking the embassy and the police. Defence lawyers strongly criticised the trial and the main charges, including premeditated attacks organised by an armed gang, with possible sentences ranging from five years in jail to the death penalty.
"These protests were part of a spontaneous reaction throughout the [Muslim] world against attacks on our sacred symbols," said one of the defence lawyers, Slah Barakati.
He said the trial was a result of the Tunisian judiciary bowing to Western pressure.
The government has accused Saif Allah Bin Hussein, a former al-Qaeda fighter in Afghanistan known as Abu Iyadh, of orchestrating the embassy attack.