反应装甲（英语：Reactive armour）是一种主要通过爆炸来破坏射中炮弹以降低其攻击力的装备。

反应装甲的设想最早由苏联人提出，但是反应装甲首次运用于实战则是1982年中东战争中的以色列。

二战后的反坦克炮弹和RPG之类反坦克武器大量用了成型装药技术，当射流击中反应装甲时，反应装甲会即时爆炸，借由爆炸的反作用能量来反弹来袭之砲弹，进而保护坦克。此类反应装甲被称为爆炸式反应装甲（ERA），但也有一种反应装甲是非爆炸式的（NERA），此种装甲的设计是两层金属内有一个夹层由橡胶之类制作成一个盒形，当射流遇到内夹层时它会膨起从而使射流失效。有观点认为中国99式坦克的一种改型用的空心楔型装甲块就是此种构造。

Reactive armour is a type of vehicle armour that reacts in some way to the impact of a weapon to reduce the damage done to the vehicle being protected. It is most effective in protecting against shaped charges and specially hardened kinetic energy penetrators. The most common type is explosive reactive armour (ERA), but variants include self-limiting explosive reactive armour (SLERA), non-energetic reactive armour (NERA), non-explosive reactive armour (NxRA), and electric reactive armour. Unlike ERA and SLERA, NERA and NxRA modules can withstand multiple hits, but a second hit in exactly the same location will still penetrate.