They were also ordered to collectively pay $100m in damages, BBC reports.
This is the third guilty verdict against Ben Ali, who fled in January to Saudi Arabia, which has since failed to extradite him despite requests from Tunisia.
Ben Ali's overthrow in January after weeks of protests inspired the wave of "Arab Spring" uprisings that spread across the Middle East and North Africa this year.
He fled with members of his close family to Saudi Arabia, where he is now in exile, after 23 years in power.
He was jailed for charges relating to using his power to obtain property at prices well below the market value in the capital, Tunis.
He and his son-in-law, businessman Sakher El Materi, were sentenced to 16 years in prison, Reuters reports.
His daughter, Nesrine, who is married to El Materi, was given an eight-year jail term.
Ben Ali was first sentenced in June, along with his wife Leila, to 35 years in prison for embezzlement and misuse of state funds.
Earlier this month, he was convicted on charges of possessing illegal drugs and weapons after a one-day trial and given 15 years in jail.
His critics say there was widespread human rights abuses and a lack of democracy under his rule, BBC reports.
His case is being watched closely in Egypt, where former president Hosni Mubarak is due to stand trial over the killing of protesters who unseated him after 30 years in power, Reuters reports.