板甲（英语：Plate armour）是以金属制成的一整块金属板盔甲、用于保护全身。从古希腊罗马的古典时期就开始使用，盛行于中古欧洲封建时代。古希腊罗马时期使用青铜材料，14世纪出现了用熟铁浇铸的板甲，15－16世纪后出现了锻打的软钢制板金甲，后期演变为四分之三甲等。

Plate armour is a historical type of personal body armour made from iron or steel plates, culminating in the iconic suit of armour entirely encasing the wearer. While there are early predecessors such as the Roman-era lorica segmentata, full plate armour developed in Europe during the Late Middle Ages, especially in the context of the Hundred Years' War, from the coat of plates worn over mail suits during the 13th century.