Social influence is omnipresent, explicitly and implicitly influencing people’s preferences and behaviors. Recently, neuroscientists have begun to contribute to our understanding of social influence, providing insight into mental processes that occur in real time without the need for participant introspection. The current dissertation aims to build our understanding of social influence by examining the neural mechanism that underlie receiving feedback about others’ preferences, as well as the mechanisms that underlie conformity to others’ preferences. In order to examine these relationships, the current dissertation examined four questions. First, we examined which neural mechanisms underlie processing social feedback and conformity across 249 people, making it the largest study of social influence in the brain to date. Next, we examined whether SES (high versus low) moderates neural mechanisms associated with social influence processing and conformity. Third, we examined whether development (adolescents versus young adults) moderates neural mechanisms associated with social influence. Finally, we examined whether the relationship between SES and social influence processing and conformity is different depending on developmental trajectories. Results from the current dissertation provide robust evidence for a core set of brain systems involved in conflict detection and mentalizing that are implicated in social influence across groups. We address previous methodological limitations stemming from diverse methods employed to study social influence across different past studies of influence. In addition, we begin to show evidence that socio-demographic factors and development may moderate the neural bases of social influence. Taken together the findings from the current dissertation advance our understanding of social influence by providing evidence for a set of core mechanisms involved in social influence. We do not find robust evidence for differences in neural processing associated with socio-demographic factors, but highlight some subtle differences and discuss possibilities for future neuroimaging research that can more definitively address commonalities and differences across groups.