Armour or armor (see spelling differences) is protective clothing intended to defend its wearer from intentional harm in combat and military engagements, typically associated with soldiers. Armour has been used throughout recorded history, beginning with hides, leather, and bone, before progressing to bronze, then steel during the middle ages, to modern fabrics such as Kevlar^®, Dyneema^® and ceramics.

Armour was also commonly used to protect war animals, such as war horses and elephants. Armour for war horses was called barding. Armour has also been produced for hunting dogs that hunt dangerous game, such as boars. Since World War I, armoured fighting vehicles are protected by vehicle armour.

In modern usage, Armour, or the armoured is also a heavily armoured military force or organization, such as heavy infantry or heavy cavalry (as opposed to light infantry or cavalry). In modern armoured warfare, armoured units equipped with tanks serve the historic role of heavy cavalry, and belong to the armoured branch in a national army's organisation (sometimes, the armoured corps). Heavy infantry have been replaced by mechanised infantry.