The curfew from 8 pm until 5 am would begin today because the attacks on public and private property "represent a danger to the country and its citizens," the Interior Ministry said.
The previous night, police stations came under attack and security officers used tear gas to repel protesters armed with stones and Molotov cocktails.
In housing projects on the outskirts of the capital, Tunis, roving groups of young people pillaged a bank and looted stores and warehouses.
"Are we not Tunisians too? It's been four years I've been struggling. We're not asking for much, but we're fighting for our youth. We struggled so much for them," said Leila Omri, the mother of an unemployed graduate in Kasserine.
Tunisia has been under a state of emergency since a suicide bombing in November killed 12 members of the presidential guard in the heart of Tunis an attack that capped an unusually violent year for Tunisia. That bombing, as well as attacks earlier in the year against the Bardo museum and the tourist beach town of Sousse, were claimed by the Islamic State group.