This paper elucidates issues in anthropological diversity, as it affect sustainable national development in Nigeria. The paper contextualizes this in behavioural paradigms and adopted interpretivism to construct meanings of social reality. The fundamental assumption of this approach is that social events do not share strict parametric accuracy with matter. Language, ethnicity, religion, economic life, culture, tribe, etc were identified as elements of anthropological diversity in Nigeria. The paper contended that diversity threatens cohesion, but tends to deliver greater opportunities when managed positively. The paper thus suggests 3 series of behaviour modification intervention to encourage sustainable national development in Nigeria.