Samir Ben Amor, a lawyer for one of the 44 defendants, said the verdicts were handed down over a massacre at the popular Sousse resort and another attack on the country’s famous Bardo Museum.
Thirty Britons were killed in the mass shooting in Sousse which left 38 people dead, while another UK citizen died in the Bardo assault, which killed 22 in total. Other defendants received jail terms ranging from 16 years to six months, while the charges against 27 of the suspects were dismissed, according to Mr Ben Amor.
None of the defendants received the maximum penalty of capital punishment for a charges that included premeditated murder, threatening national security and belonging to an extremist-linked group.
The prosecution has said it will appeal the verdicts.
Police say the defendants denied having participated directly in the March and June 2015 attacks during their questioning, but several of them acknowledged having provided logistical assistance.
On March 18 2015 at the Bardo Museum in Tunis, 22 people were killed by extremists.
Then on June 26 in the coastal city of Sousse, attacker Seifeddine Rezgui walked onto the beach of the Imperial Hotel and used an assault rifle to shoot tourists, killing 38 people.
Police killed Rezgui about 15 minutes later.
Christopher and Sharon Bell, from Leeds, were both shot dead close to the hotel swimming pool.
Mr Bell, 59, and his wife, 54, were described at an inquest as a loving couple who doted on their two grandchildren. They had two sons and a daughter and lived in Killingbeck.