A physical protection system (PPS) integrates people, procedures, and equipment for the protection of assets or facilities against theft, sabotage, or other malevolent intruder attacks. In this paper we focus on the architecture modeling of PPS to support the communication among stakeholders, analysis and guiding the systems development activities. A common practice for modeling architecture is by using an architecture framework that defines a coherent set of viewpoints. Existing systems engineering modeling approaches appear to be too general and fail to address the domain-specific aspects of PPSs. On the other hand, no dedicated architecture framework approach has been provided yet to address the specific concerns of PPS. In this paper, we present an architecture framework for PPS (PPSAF) that has been developed in a real industrial context focusing on the development of multiple PPSs. The architecture framework consists of six coherent set of viewpoints including facility viewpoint, threats and vulnerabilities viewpoint, deterrence viewpoint, detection viewpoint, delay viewpoint, and response viewpoint. We illustrate the application of the architecture framework for the design of a PPS architecture of a building.