Mess dress uniform is the most formal (or semi-formal, depending on the country) type of evening-wear uniform used by military personnel, police personnel, and other uniformed services members. It frequently consists of a mess jacket, trousers, white dress shirt and a black bow tie, along with orders and medals insignia. Design may depend on regiment or service branch, e.g. army, navy, air force, marines, etc. In modern Western dress codes, mess dress uniform is the supplementary alternative equivalent to the civilian black tie for evening wear. Mess dress uniforms are typically less formal than full dress uniform, but more formal than service dress uniform.
Prior to World War II, this style of military uniform was largely restricted to the British and United States Armed Forces, although the French, German, Swedish and other navies had adopted their own versions of mess dress during the late 19th century, influenced by the British Royal Navy.
While mess dress uniform is predominantly worn at occasions by commissioned officers and non-commissioned officers, it may also be worn as an optional uniform by some senior enlisted personnel. It is also sometimes worn by members of royal courts or certain civilian uniformed services.
Mess dress uniform is also known as mess uniform and, more informally, as mess kit.
The Australian Army has separate mess kits for summer and winter. The summer mess kit is a white jacket, almost identical between different branches of the army. The winter mess kit is made of thicker material, with jackets in the colour (scarlet or dark blue) of the wearers' corps. The winter mess dress includes a waistcoat. Both kits have the same barrathea blue trousers, but trousers vary in the colour and width of leg stripe denoting corps. Women's mess attire is the same, except that women may wear a skirt instead of trousers. Both versions are worn with a bow tie and white shirt; Marcella for winter and plain for summer.
The Royal Australian Air Force has different mess uniforms for summer and winter.