Islam arrived much earlier in the Sahel, by the 15th century a number of areas had been touched by the Muslim presence in one way or the other. Different factors contributed to the penetration of Islam in the Sahel. Trade was the most outstanding vector of the arrival of this new religion in the vast regions of the West African territories. Subsequently, the slave trade actively contributed to the spread of Islam in the region in the later centuries, as some of them eventually took to the religion of their captors as a way of reducing the harsh treatment. The paper examines how the enslaved Muslims contributed to the Islamization of the Sahel in West Africa. Islamization of West Africa was an ongoing process since the inception of Islam, but the enslavement of some local Africans contributed indirectly to the indigenization and spread of Islam.