Collective memories which is a group’s shared representations of its past and which has the potentiality of shaping identity was examined in the context of a highly pluralistic society in the study. The research was conducted among 650 purposively selected participants from the three major ethnic groups in Nigeria through an online survey. The study seeks to know if pleasant collective memories will positively influence ethnic (subgroup) identification and national (superordinate) identification, and if on the other hand, unpleasant collective memories will be positively associated with ethnic identification but negatively associated with national identification. The study also seeks to know if victim beliefs will influence engagement in collective actions against authorities for justice. Respondents were measured on collective memories, victim beliefs, ethnic and national identifications scales. Findings of the study through a Latent Class Analysis (LCA) and Path Model Analysis indicate that pleasant collective memories positively influenced ethnic identification and national identification b = .56, SE = .15, p < .001, b = .67, SE = .14, p < .004, respectively. Also, result indicates that unpleasant collective memories has a significant positive influence on ethnic identification, but a significant negative influence on national identity. (b= 0.239, -0.058), respectively. Furtherance to this, Victim belief was found to be a predictor of collective action. (b = 0.251, p-value = 0.009 95% CI [0.12, 0.90], although, pleasant collective memories reduce the likelihood of collective action, (b = -0.716, p-value = 0.000). The study discusses how these dynamics influence ethnic group’s relations with other ethnic groups and the government of a pluralistic society.