This guide is for commanders and staff who are training for, or operating in a multinational environment. The primary focus is on aiding U.S. Army units to better plan, prepare, execute, and assess multinational operations through improved shared understanding, mutual trust and confidence, and unity of effort with our mission partners. This guide addresses three key areas to provide improved multinational interoperability: introducing a common understanding of interoperability, exploring an interoperability framework encompassing the human, procedural, and technical domain solutions to improved interoperability, and showing how leaders can integrate "planning for interoperability" within the operations process. It includes examples that highlight key interoperability considerations and outcomes across the plan, prepare, execute, and assess phases of an operation.