According to a Medenine court spokesman Fethi Baccouche, the incident occurred off the coast of the southeastern island of Djerba on Monday.
The boat went down at dawn and 29 people were rescued, told AFP, adding five men and four women were among the dead and that the cause of the sinking remained unknown.
The Tunisian National Guard said it was alerted by four migrants who swam back ashore.
Tunisia and neighbouring Libya are often departure points for migrants seeking better lives in Europe, risking dangerous Mediterranean crossings.
The exodus is fuelled by Tunisia’s struggling economy, with only 0.4 percent of growth in 2023 and unemployment soaring.
Each year, tens of thousands of people attempt to make the crossing with Italy, whose Lampedusa island is only 150 kilometres (90 miles) away, often their first port of call.
Since January 1, at least 103 makeshift boats have capsized and 341 bodies have been recovered off Tunisia’s coast, the government says.
In 2023, more than 1,300 people died or disappeared in shipwrecks off Tunisia, according to the FTDES rights group.
The International Organization for Migration has said more than 30,309 migrants have died in the Mediterranean in the past decade, including more than 3,000 last year.