Afrobasket 2015 is being held in Rades, on the outskirts of the capital Tunis, having moved from the coast after two deadly attacks on tourists this year.
In June, an Islamist gunman killed 38 people at the beach resort of Sousse.
The winners of this year's tournament will be crowned African champions, as well as qualifying for the 2016 Olympics in Rio de Janeiro.
The other three semi-finalists will go into an Olympic qualifying tournament next year.
The opening match of the event is between Egypt and Gabon.
Defending champions Angola are favourites to win the tournament.
Africa's biggest basketball tournament is under way in Tunisia, after a venue change due to security concerns.