Militaria are artifacts or replicas of military, police, etc., collected for their historical significance. Such antiques include firearms, swords, knives, and other weapons such as; uniforms, helmets, other military headgear, and armour; military orders and decorations; challenge coins and awards; badges and insignia; military art, sculpture, and prints; ephemera such as cigarette cards, photographs, antiquarian books, magazines and posters; scale models and toy soldiers; and items of combat equipment and field gear.

Today, the collecting of militaria is an established hobby among many groups of people. Many European families, specifically those royal families with long martial tradition, have large collections of militaria passed down from generation to generation. Also, many people today collect militaria for investment purposes, as the value of extremely rare antiquities almost never goes down.

An alternate name, used by many dealers, for militaria is 'military antiquities' or 'military antiques'.