This paper investigated the role of youths in effective implementation of security and social development intervention in Nigeria. The Evolutionary Theory of Social Development and Human Development Theory were used to explain the role of youths in effective implementation of security and social development intervention in Nigeria, but the latter was adopted in the study due to its adequacy in addressing the problem and linking the variables under study (youths, security development and social development intervention). The study found that the role of youths in effective implementation of security and social development intervention in Nigeria cannot be overemphasized. This is because youths have been deeply involved in various self-help projects in various Local and State Governments in Nigeria. Their areas of interventions cover projects involving trade, commerce, security, Home Economics, small and medium term enterprises and agriculture, anti-corruption, counterterrorism, community policing and drug-free clubs among others. The paper concluded that youths have many means of contributing to the development of their societies. Many local and international NGOs are either initiated by the Nigerian youths or co-opt our youths to intervene in the above mentioned areas. Some of them are backed by the government to execute their activities or pressurise the government to be responsive to the citizens in the area of security and social development. This is conditioned by the youths' social and psychological disposition and level of productivity. However, the productivity of the youths and their role in the security and social development of Nigeria depends on the government's willingness to empower the youths in social, economic and political terms.