One of the most broadly accepted principles of punishment is that the severity of criminal sanctions should be proportional to the seriousness of the offence being punished. But proportionality requires a normative frame of reference – proportional relative to what underlying legal or normative values? Retributivists believe that punishment should be proportional to the offender’s degree of blameworthiness for the act(s) being punished. There are also several consequentialist (utilitarian) principles, which assess the proportionality of a penal measure relative to the expected benefits to be achieved by applying that measure. This chapter examines each of these meanings of proportionality in punishment, identifying the key elements of each concept, their similarities and differences, the ways in which common law legal systems and the German system have applied them and the possibilities for accommodating all of these principles in a single punishment model.