This study explored Nigeria and South Africa relation within the context of citizen diplomacy. We collated our date from qualitative descriptive method and hence relied on secondary data. We predicated our analytical framework on the basic propositions emanated from the theory of complex interdependent. The study among others, observed that with economic advantage as the major international political issues, states and their citizens are under anxiety not to be outwitted and outcompeted in the fast growing global interdependence and thus subscribe to the rule of reciprocal relations as foundation for cooperation. The study therefore underscored the effect of diaspora in national economic development within the rubric of international rule of reciprocity; while observing the checks of domestic values and culture of host states. Focusing on Nigeria‘s diaspora defence in South Africa, the study explored the basic factors that determine Nigeria-South Africa relations especially as it concerns the contributions of the Diaspora to national development through the application of international best practice and social relations, it equally made useful suggestions aimed at strengthening the capacity of Nigeria to achieve the foreign policy goals and to provide adequate safeguards to her citizens living in foreign countries.