Black tie, known in the United Kingdom (and also in the north-eastern United States, and Canada) as a dinner jacket and in the United States generally as a tuxedo, is a dress code for formal evening events that are not formal enough to require white tie.

Black tie is today worn at a wide variety of functions, and the corresponding female attire can range from a short cocktail dress to a long gown, depending on fashion, local custom and the hour at which the function takes place.

A Tuxedo Park insider recalls a different story of the Tuxedo Park introduction of black tie, told him in the 1920s by Grenville Kane, the last founding member of the Tuxedo Club. Kane remembered that it had been James Brown Potter who, after staying with the Prince of Wales at Sandringham in the summer of 1886, brought back the new fashion to Tuxedo and introduced it to the members of the club

The American upper classes now generally prefer the terms "black tie" or "dinner jacket" to "tuxedo", which is considered slightly vulgar.

Early evening clothes were uniformly black. The Duke of Windsor, when Prince of Wales, introduced midnight blue as an appropriate color, and even made the double-breasted dinner jacket acceptable.

The waist sash called cummerbund (or cumberbund) was borrowed after World War I, from military dress in British India.

In the days when evening dress was worn every evening, black tie developed as a form of evening dress of which the components did not require costly frequent laundering and starching, unlike white tie.

Black tie leaves a lot to the wearer's discretion compared to the far more codified white tie (e.g. single- versus double-breasted coat). Nonetheless, so far as a convention exists, it is that black tie properly consists of:

• Black short coat with silk (ribbed or satin) lapels (peaked or shawl-collared), usually without vents.
• As an alternate to the above, a white dinner jacket, suitable for warm climates, or from mid-April through Labor Day (United States and Canada)
• Black trousers with a row of braid or ribbon down each leg
• White shirt
• Black silk bow tie
• Black low-cut waistcoat (called a vest in Canada and the US), or a cummerbund
• Black socks
• Black shoes

Coloured bow ties, waistcoats and cummerbunds are widespread at parties, but not appropriate at more formal occasions. On the other hand, wearing a white bow tie with a dinner jacket is considered a grave solecism (though the first dinner jackets were worn with white ties). Coloured or patterned dinner jackets are sometimes seen but are not appropriate at formal occasions. In the United States, the wearing of a collarless shirt without a bow tie, closed with a stud or banded, has become fashionable, but would again not be seen e.g. a state dinner.

Cufflinks and shirts studs can be black, white, silver, or gold, and a white handkerchief and flower may be worn. In recent years it has become acceptable to wear state decorations with black tie at state events. In such cases only one neck ribbon and one breast star are worn, with miniature medals.

In the United Kingdom, it is felt in some circles that wing collars are properly the preserve of white tie, and that a shirt with a soft turn-down collar should be worn with black tie. However, in its earliest form black tie was always worn with a stiff white shirt and stiff wing collar. White waistcoats, such as those worn with white tie, remain an acceptable alternative to black.

Black tie, having originated as an informal dress code for e.g. dining at home, has no single accepted form of headgear. Generally a soft black felt hat such as a homburg may be worn together with an overcoat.

Mess dress

In the armed forces, officers normally wear mess uniforms which correspond to evening dress or black tie. These vary according to the regiment or corps, but usually involve a short Eton style jacket that comes to the waist. Some forms include white shirts and black bow ties, while others have high mandarin collars that fasten around the neck. They are usually brightly coloured and ornamented with gold lace and buttons, corresponding to the regiment or corps.

In the Royal Navy there is a distinction between "mess dress", which is worn at white tie events, and "mess undress", which is worn at black tie events. Both are worn with a black bow tie, however mess dress is worn with a white waistcoat instead of the usual blue.

Scottish dress

Scottish dress is often worn at black tie events, especially at Scottish reels and ceilidhs. While there is a more formal version which may be worn when the dress code is white tie, the black tie version is much more common, even at white tie events.

The traditional black tie version of Highland dress consists of:

• Black Prince Charlie jacket
• Black waistcoat
• Kilt
• White shirt
• Black bow tie
• Black Ghillie brogues
• White kilt hose
• Flashes

Other colours for both the Prince Charlie jacket, and the hose are seen.

The Lowland version of black tie is a variation on normal black tie, with trews worn with a normal dinner jacket or Prince Charlie jacket. Trews are also often worn during the summer and in a warm clime.

When it is worn

In the United Kingdom black tie is only properly worn in the evening, i.e. after 6 p.m.. However, in some other places such as the United States, it has become common to wear black tie at four o'clock weddings and evening weddings. At Harvard in the 1960s, young men in dinner jackets seen during the late afternoon hastening towards an event would be hailed by ironic cries of "Check, please!"

Black tie is worn at many private and public dinners, dances, and parties, and it would be impossible to draw up a comprehensive list. At the most formal end it has taken over from white tie at many occasions where the latter would formerly have been worn, e.g. by orchestra conductors. In the United States, it commonly appears at proms and is worn by men at weddings even during the day. (see tuxedo rental).