Abstract Hypotheses about the worldwide colonization routes of the melon fly, Zeugodacus cucurbitae (Diptera: Tephritidae), are mainly based on sparse historical records. Here we aimed at reconstructing the invasion and colonization history of African mainland based on the microsatellite population genetic structure of Z. cucurbitae. A total of 332 specimens were sampled in 17 localities from East, West and Central Africa and genotyped at 19 microsatellite markers. A STRUCTURE analysis showed intracontinental population structuring with populations from Uganda diverging from those of Tanzania and populations from Burundi and Kenya showing traces of admixture with West African samples. Approximate Bayesian Computation provided s upport to the hypothesis of an initial introduction Z. cucurbitae into East Africa and a subsequent expansion to West Africa. Parameter estimates suggested that these events are in accordance with the historical records of Z. cucurbitae on the African continent (viz. 1936 in East Africa and 1999 in West Africa) and allowed excluding alternative hypotheses considering older or multiple introductions of Z. cucurbitae. .