The city's population estimates range from over 500,000 to 1,500,000; the number for Greater Lagos is estimated at 6,000,000 (1990). Population densities can also be as high as 20,000 per square mile in some places.

Over two-thirds or 70 percent of the city's population are Yorùbá-speaking, with the remainder divided between non-Yorùbá speaking Nigerians, Africans, and non-African residents. The Yorùbás are also the majority group in Greater Lagos though long-term residence and the urge to partake in available economic opportunities may have encouraged assimilation on the part of non-Yorùbá immigrants. Ajégúnlè near Àpápá is the only mainland town in Greater Lagos where ethnic Yorùbás are a numerical minority.