A bearskin is a tall fur cap derived from mitre caps worn by grenadier units in the 17th and 18th centuries. Initially worn by only grenadiers, bearskins were later used by several other military units in the 19th century. The bearskin cap continued to see use in battle during the mid-19th century, although by the 20th century, it was only used for parade dress. In the 21st century, the bearskin cap is retained by select military units as a prominent element of their ceremonial and full dress uniforms.

Use of the bearskin caps evolved from mitre caps used by grenadier units. Grenadiers adopted the mitre cap in favour of wide-brimmed caps in the 17th century to provide them with greater mobility when throwing grenades. To prevent the mitre cap from sagging and to provide it with a more impressive appearance, mitre caps were adorned with a metal front plate or fur. Mitre caps with metal front plates were first adopted by the Prussian Army and were later adopted by other Protestant countries, although the trimming of mitre caps with fur became more prevalent in Roman Catholic countries.

The earliest record of a bearskin-like cap being worn by soldiers in Europe was during the mid-17th century, although its widespread adoption did not take place until 1761, when French grenadiers began to wear tall fur caps resembling the Prussian mitre cap. The purpose appears to have been to add to the apparent height and impressive appearance of these troops both on the parade ground and the battlefield. These fur caps developed into the large bearskin caps worn by the French Imperial Guard. The British Grenadier Guards adopted the headdress after their victory at the Battle of Waterloo in 1815, with other British units and European militaries adopting the headdress in the years after.

The headdress continued to see military service during the mid-19th century, with British foot guards and the Royal Scots Greys wearing bearskins in battle during the Crimean War. However, by the mid-19th century, the expense of acquiring bearskin caps and the difficulty in maintaining them in good condition under campaign conditions led to some armies limiting the use of the headdress to specific formal occasions. Military units, like the Italian 1st Regiment "Granatieri di Sardegna", eventually discontinued the use of the headgear altogether during that century.

The British continued to use the headdress during peacetime manoeuvres until the introduction of khaki service dress in 1902. Immediately before the outbreak of World War I in 1914, bearskins were still worn by several British, Belgian, Danish, German, Russian, and Swedish units as a part of their ceremonial/parade dress. Several regiments that retired the use of the headdress during the 19th century, including units in Italy and the Netherlands, also readopted it for ceremonial use during the 20th century.

As of 2020, there were 14 countries whose militaries used bearskin as a part of their ceremonial uniforms. Some of these units wear bearskins made out of real bear fur, while other units use caps made out of synthetic fibres. In addition to military units, several civilian marching bands have also incorporated the bearskin cap as a part of their uniforms.

The Pipes and Drums Band of the 3rd Battalion, Royal Australian Regiment are authorised to wear a bearskin cap as a part of its ceremonial dress.^{[better source needed]}

Two units in Belgium use the bearskin cap, the Belgian Royal Escort of the Belgian Federal Police, and the Regiment Carabiniers Prins Boudewijn – Grenadiers of the Belgian Armed Forces Land Component.