Reports have suggested the onset of fertility transition in Nigeria and speculations are rife about the factors driving the observed fertility changes. This study investigates if and how ‘desired number of children’ influences the observed fertility change in the country, utilizing information collected from twenty-four focus group discussion (FGD) sessions conducted across the country. The results show that people are revising the number of children they are having downward, but the desired number of children remains high. Religion and culture are key drivers of current desired number of children but changing socio-economic factors greatly limit the actual number of children people have. The desired number of children does not play noticeable role in the observed fertility transition in Nigeria, posing significant challenges for policies and programmes that aim to lower desired number of children for sustainable fertility level in the country.