Paulo Machava, publisher of the online Diario de Noticias, was gunned down while taking his daily morning jog along one of the capital's main streets.
"A group of armed individuals fatally shot Paulo Machava before fleeing," police spokesman Arnaldo Chefe told a news conference.
The gunmen, who was driving a white pick-up truck, fired between four and six shots before speeding off, according to preliminary police investigations.
Street vendors who witnessed the attack confirmed to AFP that the shots were fired from a vehicle.
The style of killing was similar to that in early March of Gilles Cistac, a naturalised Mozambican citizen of French origin and a constitutional law expert who was highly critical of the government.