ABSTRACT This essay examines the complex interplay between religious, ethnic, and regional identities in Nigerian politics, challenging the idea that religion solely dictates political behavior. It delves into the manipulation of identities for political advantage, with an emphasis on religion. The Social Identity Theory (SIT) is discussed, highlighting the cognitive processes in forming social identities and their role in promoting in-group bias and out-group prejudice. The novel contribution that this essay makes is the introduction of what I termed the ‘Shared Interest Theory’ or the ‘Common Interest Theory,’ arguing that changes in interests, both tangible and intangible, can trigger shifts in social identity and group dynamics. This theory offers a rational framework for understanding social identity dynamics, providing insights for promoting social cohesion in diverse societies. This framework on identity and politics underscores the importance of recognizing and addressing the divergent interests of different groups to mitigate conflicts and foster social harmony.