In this chapter, we survey existing knowledge on the evaluation of security mechanisms by defining an evaluation design space that puts existing work into a common context. Given the significant amount of existing practical and theoretical work, the presented systematization is beneficial for improving the general understanding of the topic by providing an overview of the current state of the field. The evaluation design space that we present is structured into three parts, that is, workload, metrics, and measurement methodology—the standard components of any system evaluation scenario. The discussions in this chapter are relevant for the evaluation of a wide spectrum of security mechanisms, such as firewalls and AC systems.