​We present a Systematization of Knowledge on tangible privacy and security interfaces (TaPSI). Tangible interfaces provide physical forms for digital interactions that can offer significant benefits for privacy and security applications by making complex and abstract security concepts more intuitive, comprehensible, and engaging. Through a literature survey, we collected and analyzed 80 publications. We identified terminology used in these publications, addressed usable privacy and security domains, contributions, applied methods, implementation details, and opportunities or challenges inherent to TaPSI. Based on our findings, we define TaPSI and propose the TaPSI Research Framework, which guides future research by offering insights into when and how to conduct research involving TaPSI as well as a design space of TaPSI.