As the link between psychology and economics has grown, so too has research on the link between personality traits and economic behavior. We build on this previous work, bringing to light the relationship between personality traits and contributions in a one-shot public goods game. We find that contributions to the public good are smaller for rational participants as measured by the Rational-Experiential Inventory—revised 40 (REI-40) item scale. We find no effect on contributions for the measures of the Big Five personality traits or the remaining measures from the REI-40.