We investigate a novel link between self-concept and social decision making. Motivated by theories of evolutionary psychology and memory representation, we posit that self-concept clarity, a concept combining the organization and accessibility of self-related memory representations, can promote better decision making in situations involving other persons. In two pre-registered, correlational studies (total N = 702), we assessed the relationship between self- concept clarity and decision performance and observed substantial, positive relationships. Crucially, these relationships could not be accounted for by measures of processing speed or social preferences suggesting a direct link between self-concept clarity and decision performance in a social context. We conclude by discussing how this novel finding may share a common pathway with other, established links between the organization of mental representations and cognitive performance.