A platoon is a military unit typically composed of two to four squads, sections, or patrols. Platoon organization varies depending on the country and the branch, but a platoon can be composed of 20-50 troops, although specific platoons may range from 10 to 100 people. A platoon is typically the smallest military unit led by a commissioned officer. The platoon leader is usually a junior officer—a second or first lieutenant or an equivalent rank. The officer is usually assisted by a platoon sergeant.

Rifle platoons normally consist of a small platoon headquarters and three or four sections (Commonwealth) or squads (United States). In some armies, platoon is used throughout the branches of the army. In a few armies, such as the French Army, a platoon is specifically a cavalry unit, and the infantry use "section" as the equivalent unit. A unit consisting of several platoons is called a company or a battery.