A fascist paramilitary is a fighting force - whether armed, unarmed, or merely symbolic - that is independent of regular military command and is established for the defence and advancement of a movement that adheres to the radical nationalist ideology of fascism. Such a paramilitary is similar to other radical political fighting forces, such as the Red Brigades of communism or black blocs of anarchism. Since fascism is such a militarist ideology, there are very few varieties of fascism where paramilitaries do not play a central role, and some kind of paramilitary participation is almost always a basic requirement of membership in fascist movements. Fascist paramilitaries have seen action in both peacetime and wartime. Most fascist paramilitaries wear political uniforms, and many have taken their names from the colours of their uniforms.

The first fascist paramilitary was the Blackshirts of Italian Fascism led by Benito Mussolini. While many of the Blackshirts were former members of the Arditi who had fought in World War I or the Fascio of the immediate post-war years, the most direct inspiration for the first fascist paramilitary was Giuseppe Garibaldi's Redshirts.