The sub-Saharan migrants were trying to cross the Mediterranean to reach Italy.
It is the latest in a string of migrant boat capsizes off Tunisia's coast in the last few days, with five others sinking in the past four days.
This comes after Tunisia launched a campaign against undocumented African migrants.
Meanwhile, Italian officials on the island of Lampedusa say they are overwhelmed, after a record 2,500 migrants arrived in the last 24 hours.
The Italian far-right Prime Minister, Giorgia Meloni, has warned Europe risks seeing a huge wave of refugees arriving on its shores.
Tunisia has become a hub for migrants who wish to make it to Europe, with UN figures showing at least 12,000 migrants who landed on Italy's shores this year left from Tunisia. That figure was just 1,300 in the same time period last year.
However, the Tunisia coast guard say they are taking steps to stop the migrant crossings, having halted around 80 vessels headed for Europe in the past four days, according to the Reuters news agency. It also says it has detained more than 3,000 migrants, the same agency reports.
In a controversial speech last month, Tunisia's president accused sub-Saharan African migrants living in the country of causing a crime wave and described them as a demographic threat.
This has led some countries, like Ivory Coast and Guinea, to repatriate their citizens due to an increased climate of intolerance in Tunisia.
Tunisia's economy is in a poor state, and is facing crisis after negotiations with the the International Monetary Fund (IMF) stalled.
The US Secretary of State Antony Blinken has also warned that Tunisia urgently needs to reach a bailout deal with the IMF.
