Whenever the demand for health care exceeds existing resources, rationing becomes imperative. Current lifestyle-induced illnesses increase the pressure on health systems and actualize the discussion concerning the relevance of personal responsibility in health care allocation decisions. In a publicly financed health care system, it is important that prioritysetting decisions reflect social values. This article explores whether personality traits such as dispositional optimism and tolerance, as well as healthy behaviors, influence preferences for the prioritization of patients based on their lifestyles. An online questionnaire was used to collect data from a sample of 581 Portuguese citizens. Quantitative data analysis was performed through structural equation modeling. The results showed that optimism is positively related to the acceptance of personal responsibility as a bedside rationing criterion, whereas tolerance indicated compassion for the illness of others and, therefore, better adherence to the externalization of responsibility and less responsiveness to accountability. Furthermore, personality did not affect respondents' predisposition to pursue healthy lifestyles, while it turned out to be a more important predictor than healthy behaviors for setting priorities among patients based on personal responsibility. Personality traits like optimism and tolerance proved to be important factors driving social values for health care rationing decisions.