The field of self-control has witnessed an unprecedented boom, not least due to the immense implications of successful and unsuccessful self-control for people’s lives. However, successful and unsuccessful self-control can take many different forms, and many conceptual problems have been raised as to what self-control is about and how to best study it. Integrating different literatures, we provide a general model of self-control which distinguishes between preventive (i.e., anticipatory) and interventive (i.e., momentary) forms of self-control. The proposed Preventive-Interventive Model (PI-Model) of Self-Control combines seven basic components: preventive strategies, desire, conflict, control motivation, volition, opportunity constraints, and behavior enactment. The resulting taxonomy helps to distinguish self-control from standard motivational processes, to define the concept of temptation, and to identify different types of self-control failure including self-monitoring failure, motivational self-control failure, and volitional self-control failure. Further, the model helps to outline five broad mechanisms through which people may be able to proactively boost self-control success.