The current work explores the predictive power of the recently proposed sixth personality dimension, Honesty-Humility, with respect to economic and cooperative behavior. It was expected that this factor should explain how decision makers allocate a valued good to themselves vs. another in the dictator and the ultimatum game. More importantly, we predicted that Honesty-Humility would explain differences between these games in which the power of the recipient to retaliate is varied. Both conjectures were corroborated in a semi-experimental study with N = 134 participants: individuals low in Honesty-Humility made more selfish decisions and only shifted towards a more fair allocation whenever the other was empowered to punish defection. Those high in Honesty-Humility, on the other hand, displayed a stable tendency for choosing a more fair solution - even when they could have defected without fearing consequences. Finally, social value orientations were shown to partially mediate the effects found.