CISA, the Department of War (DoW), and the Department of Energy (DOE), through the Zero Trust Operational Technologies Security Working Group, released Adapting Zero Trust Principles to Operational Technology, joint guidance to support organizations in applying zero trust (ZT) principles to operational technology (OT) systems and environments. The document provides considerations for system owners, operators, and security personnel, addressing challenges such as legacy infrastructure limitations, operational constraints, and safety requirements tied to physical processes. It is intended for ZT practitioners and OT stakeholders who may have limited familiarity with OT environments, while also being applicable to any organization managing OT systems. Key topics include establishing asset visibility, addressing supply chain risks, and implementing identity and access management, alongside layered security controls such as network segmentation, secure communication protocols, and vulnerability management. The guidance emphasizes a security approach that assumes a breach has occurred and prioritizes operational continuity, safety, and reliability. It aligns with the National Institute of Standards and Technology Cybersecurity Framework 2.0 functions of Govern, Identify, Protect, Detect, Respond, and Recover. The document concludes that successful implementation requires a holistic approach, adaptation of ZT principles to specific OT environments, and collaboration among IT, OT, and cybersecurity teams. By applying these principles, organizations can enhance the security and resilience of OT systems, including industrial control systems and facility automation. For additional details, refer to the CISA publication Adapting Zero Trust Principles to Operational Technology.