Despite several family planning interventions, there has been little improvement in contraceptive use in Nigeria where fertility rates have remained high for the last few decades. Using a mixed-methods approach, this thesis aims to understand the pertinent factors underlying the resistance to fertility decline in the country, with a focus on social and cultural barriers to family planning. The analyses are based on quantitative data drawn from the 2013 Nigerian Demographic and Health Survey (NDHS) and qualitative data collected from a semi-urban residential area in Ekiti State. The findings of the thesis are presented in a three paper format. The first analysis applied life tables and proportional hazard regression to NDHS data to examine the association between child mortality and fertility behaviour. The findings show that recurrent experience of child deaths exacerbate the risks to higher parity transition. The second analysis used couple dataset from the NDHS to investigate the influence of men’s contraceptive perceptions on family planning demand and use. The findings highlight that men’s perception of contraception as women’s business did not significantly influence family planning demand, however their concern that wife’s contraceptive use may lead to promiscuity was associated with lower demand for family planning and higher traditional method use. The third analysis used vignette and thematic analysis from qualitative data to examine couples’ contraceptive decision-making processes and wife’s empowerment to adopt family planning in situations where husband opposed family planning. The findings demonstrate imbalance in power relation and decision-making within marital relationships, and that women are poorly empowered to overtly use contraceptives when opposed by their partners. The findings direct the need to adopt targeted approach focusing on couples, and reorient policy and program efforts for FP counselling and behavioural changes in men. Interventions aimed at reducing fertility in Nigeria should aim at promoting child survival and family planning concurrently.