Developing countries multiply the incentive policies on education, at least for primary education and educational equity, to improve the entire educational landscape and to address problems of poverty and insecurity affecting the most of these countries and in sub-Saharan Africa in particular. The aim of our work is to verify, first, the impact of the average years of schooling and educational inequalities (proxy of human capital) on economic growth for 65 developing countries over the period 1985-2010. Second, check if the developing country growth trajectory is explained only by economic factors such as education or requires other factors, structural and conjunctural, specific to each country. We conclude that the effect of the average number of years of study is positive and significant economic growth of the countries in our sample and the predominance of conjunctural factors. However, it appears that educational inequalities have a negative and significant impact on the growth of these countries. The distinction between the group of low-income countries, middle and high shows the existence of a threshold below which education has no effect on economic growth.