The perspective of non-economic social sciences in designing and implementing development programmes is marginalized in discourse and practice. This paper examines the empirical role of social science knowledge in development programmes designed by official development agencies and implemented by governments in developing countries such as Nigeria. The focus is on programmes run by specialised knowledge-based organization, such as – the United Nations and World Health Organisation (WHO). Though the WHO defines health as a social goal, the study has found an exclusivity of biomedical approach and the neglect of social science perspectives in the design of public health interventions. Interventions remain vertical entities that are often divorced from the priorities and needs of beneficiaries and the national health system in Nigeria. The paper argues that mainstreaming social science knowledge in programme design and implementation is critical to effective delivery.