Military organization or military organisation is the structuring of the armed forces of a state so as to offer such military capability as a national defense policy may require. In some countries paramilitary forces are included in a nation's armed forces, though not considered military. Armed forces that are not a part of military or paramilitary organizations, such as insurgent forces, often mimic military organizations, or use these structures, while formal military organization tends to use hierarchical forms.
The use of formalized ranks in a hierarchical structure came into widespread use with the Roman Army.
In modern times, executive control, management and administration of military organization is typically undertaken by governments through a government department within the structure of public administration, often known as a ministry of defence or department of defense. These in turn manage military branches that themselves command formations and units specialising in combat, combat support and combat-service support.
The usually civilian or partly civilian executive control over the national military organization is exercised in democracies by an elected political leader as a member of the government's cabinet, usually known as a minister of defence. In presidential systems, such as the United States, the president is the commander-in-chief, and the cabinet-level defense minister is second in command. Subordinated to that position are often secretaries for specific major operational divisions of the armed forces as a whole, such as those that provide general support services to the military, including their dependants.
Then there are the heads of specific departmental agencies responsible for the provision and management of specific skill- and knowledge-based services such as strategic advice, capability development assessment, or military science provision of research, and design and development of technologies. Within each departmental agency will be found administrative branches responsible for further agency business specialization work.