This manual provides a guide for Army commanders and staffs operating in a multinational environment. It applies across the full spectrum of military operations. It provides general information on important topics necessary for conducting multinational operations. However, it also lists questions that multinational partners need to address to improve their mission effectiveness and efficiency. Every multinational operation differs. The purpose, character, capabilities, composition, and scope of a multinational operation are functions of changing missions. These missions are magnified by the complexities of two or more armies operating together. Each member nation brings its own view and methods of operations. This manual blends key points of Joint Publication (JP) 3-16 into its approach to ensure consideration by Army elements of a joint force. It addresses the Army's roles and functions within a multinational operation. The focus is on responsibilities for conducting operations as part of a multinational force. It also addresses multinational leadership and provides examples of possible command relationships. Finally, it addresses planning considerations of the multinational commanders and their staffs. Information contained herein will help other national forces and other services plan and conduct multinational operations with U.S. Army forces. Commanders must recognize those areas within multinational control and those areas under national control. This is a key issue that crosses all functions. Recognizing this issue will enable commanders and their staffs to focus on important issues. It will enable them to function more effectively and efficiently. Multinational partners conduct multinational operations to prevent, contain, or resolve conflicts that may pose threats to common national interests. This manual provides a handy reference of fundamental issues and interfaces that must be addressed to promote a successful multinational operation. While North Atlantic Treaty Organization (NATO) and the American, British, Canadian, Australian Armies Program (ABCA) have achieved some levels of standardization in certain areas, no comprehensive common doctrine exists between the armies. This manual does not fill this gap. It will, however, assist the multinational commander in understanding and developing solutions to create an effective fighting force. This manual incorporates selected information from NATO standardization agreements (STANAGs) and ABCA standards. However, it does not reproduce these documents. This manual does not repeat staff planning procedures or the military decision making process. It does include some of the differences in doctrine, tactics, techniques, and procedures of selected nations with which the United States has operated on numerous occasions. This manual takes into account the full continuum of operations and varying political objectives, force compositions, operating areas, and other factors. It also considers some general similarities in multinational operations. Because of varying compositions and varying political objectives, consensus is extremely difficult to obtain. Harmonization of the multinational force is critical to ensure unity of effort. The primary audience for this manual is commanders of ARFORs, Army Service component commanders, and other senior leaders and their staffs. This manual will also assist Army branch schools teach multinational Army operations. This publication applies to the Active Army, the Army National Guard (ARNG)/Army National Guard of the United States (ARNGUS), and the United States Army Reserve (USAR) unless otherwise stated.