Despite the fact that a lot of factors have been adduced as the bane of poor performance of public sector management in Nigeria, the surreptitious consequence of religious bias on public sector management have not been investigated. This research attempted to unravel how the underlying factors of religious bias influence the behaviours and functions of public sector managers. Hence, this study examined the relative effect of religious bias and its latent elements on public sector management in Ogun State, Nigeria. Having adopted a survey research design, the study used stratified random sampling technique to determine a sample size of 371 from a population of 5,059 employees in Ogun State public service. In addition, validated questionnaire was used to generate data for analysis. Interestingly, findings revealed that though religious bias had a significant effect on public sector management (Adj. R2 = 0.735; F(3, 367) = 342.632, p <0.05), religious sectionalism, which is one of the latent elements of religious bias had a negative effect on public sector management (β1= -0.805, t = -9.376, p<0.05). The study concluded that religious bias influences the behaviours and functions of public sector managers in Ogun State, Nigeria. It recommended that government and public management practitioners should discourage public sector managers against the use of certain aspect of religion that makes them to be selective and biased in the execution of official responsibilities.