This paper focused on three dominant psychological theories--Cognitive Dissonance, Relative Deprivation and Campus Ecology that have been evolved to explain student unrest, to determine their ability to account for the phenomenon in Nigerian universities. It found that none of the theories could all alone holistically account for all the causal factors (non-participation in decision-making, academic stress, welfare problems, changing value systems of students, parental influence, teacher influence and contemporary national issues) in student unrest in Nigerian universities. A synthetic theory, which embodies the three theories examined, was therefore advocated to account for all the causal factors in student unrest in Nigerian universities.