Marines are a branch of a nation's armed forces intended to mount amphibious operations. Many countries describe these forces as "Naval Infantry". In most countries, Marines are not a separate service but rather an extension of the Army or Navy.

The role of a Marine force does differ between nations, and its composition may vary from nothing, to light infantry, to an all arms organization with infantry, armour, aviation, and all the support required to sustain that on the battle field.

This category contains articles about marine forces. Articles about individual Marines can be found through their home nation's related Marine article.