Author: This study examines the effect of family type and ethnic differences in lifetime fertility in three selected West African countries. Using the Demographic and Health Survey datasets of a weighted sample of 10,324 ever married women in Burkina Faso(2010), 5,099 in the Gambia(2013) and 20,014 in Nigeria(2013), the mean children ever born was higher among Gourmatch ethnic group in Burkina Faso (4.45), Fula in Gambia (4.05) and Hausa/Fulani in Nigeria (4.68). Further analysis using Poisson Regression showed that lifetime fertility was significantly higher by 29% among the polygynous family in Burkina Faso, 46% in Gambia and 25% in Nigeria than among the monogamous family. Age at marriage, age at first birth, wealth status and educational attainment of women were significantly associated with lifetime fertility. Findings suggest that lifetime fertility will reduce if pro-natalists’ attitude, poverty, age at first marriage and age at first birth could be properly addressed. Keywords: Ethnicity, Family Type, Lifetime Fertility, Monogamous, Polygynous