The Blackshirts (Italian: camicie nere, CCNN, or squadristi) were Fascist paramilitary groups in Italy during the period immediately following World War I and until the end of World War II. Blackshirts were officially known as the Voluntary Militia for National Security (Milizia Volontaria per la Sicurezza Nazionale, or MVSN).

The term was later applied to a similar group serving the British Union of Fascists before World War II, to the SS in Nazi Germany, and to members of a quasi-political organization in India.

Inspired by the military prowess and black uniforms of the Arditi, Italy's elite storm troops of World War I, the Fascist Blackshirts were organized by Benito Mussolini as the military arm of his Fascist political movement and a tool for violent Fascist Italianization of primarily ethnic Slovenes and Croats on ex-Austro-Hungarian territories given to Italy in exchange for joining Great Britain in World War I. Slovenes from the western part of contemporary Slovenia, who were subjected to Fascist Italianization since the Treaty of Rapallo, experienced Fascist brutality personified by the fate of Lojze Bratuž, a Slovene choirmaster who led several Slovene language church choirs, being tortured by Black Shirts, forced to drink petrol (and engine oil) because he resisted the italianization of Slovenian names and surnames by Fascist Italy, which begun as early as 1926. Already in 1920, they burnt the Slovene National Hall in Trieste.

Sir Oswald Ernald Mosley, 6th Baronet, of Ancoats, (16 November 1896 – 3 December 1980) was an English politician, known principally as the founder of the British Union of Fascists. He was a Member of Parliament for Harrow from 1918 to 1924 and for Smethwick from 1926 to 1931, as well as Chancellor of the Duchy of Lancaster in the Labour Government of 1929–1931.

Mosley was the eldest of three sons of Sir Oswald Mosley, 5th Baronet, of Ancoats (29 December 1873 - 21 September 1928), and wife Katharine Maud Edwards-Heathcote (1874–1950), the second child of Captain Justinian Edwards-Heathcote of Market Drayton, Shropshire. Mosley's family were Anglo-Irish. His branch were prosperous landowners in Staffordshire, seated at Rolleston Hall, near Burton-on-Trent. Through the intermarriage common among the British upper classes, the 5th Baronet was the third cousin of the Earl of Strathmore, which would eventually make Oswald Mosley, the 6th baronet, fourth cousin to Queen Elizabeth The Queen Mother, who was the Earl of Strathmore's daughter, and fourth cousin once removed to Queen Elizabeth II.