Deterrence researchers have long considered the extent to which perceived certainty and severity inhibit offending. More recently, scholars have encouraged more specific investigations about the conditions under which sanction threats may deter offending. This study contributes to and extends this line of research by exploring whether morality conditions this relationship among a large sample of incarcerated felons. Results show that while certainty and morality are independently associated with a lower likelihood of offending, perceived certainty relates to offending only among those persons with high—but not low—moral beliefs.