“Auld Lang Syne" is a Scottish poem written by Robert Burns in 1788. The song asks whether old friends and times will be forgotten and promises to remember people of the past with fondness.
It is often sung to celebrate the start of the New Year at the stroke of midnight (Hogmanay [1] in Scotland). By extension, its use has also become common at funerals, graduations, and as a farewell or ending to other occasions.
Some consider it to be an international expression of friendship, fellowship and hope. Others perceive it to be a simple song, presented at the conclusion of a social gathering, remembering the past and re-affirming the importance of our future, and those important to us.

In Scotland it is often sung and danced at the end of a ceilidh. It is common practice that everyone joins hands with the person next to them to form a great circle around the dance floor. At the beginning of the last verse, everyone crosses their arms across their breast, so that the right hand reaches out to the neighbour on the left and vice versa. When the tune ends, everyone rushes to the middle, while still holding hands. When the circle is re-established, everyone turns under the arms to end up facing outwards with hands still joined. In countries other than Scotland the hands are often crossed from the beginning of the song at variance with Scottish custom.

« Auld lang syne » the song’s Scots title may be translated into English literally as "old long since", or more idiomatically, "long long ago", "days gone by" or "old times". It has been translated in French by “it is just a goodbye”.

English composer William Shield seems to quote the "Auld Lang Syne" melody briefly at the end of the overture to his opera Rosina, which may be its first recorded use. Burns borrowed the melody from Shield although they may very well both have taken it from a common source, possibly a strathspey called The Miller’s Wedding or The Miller’s Daughter.

[1] There are many customs, both national and local, associated with Hogmanay. The most widespread national custom is the practice of 'first-footing' which starts immediately after midnight. This involves being the first person to cross the threshold of a friend or neighbour and often involves the giving of symbolic gifts such as coal, shortbread, whisky, and black bun (a rich fruit cake) intended to bring different kinds of luck to the householder.
Those going out first footing should carry a bottle to offer a drink, a lump of coal to signify that the house will keep warm, bring comfort and be safe for the year, black bun, or more modernly shortbread, to signify that the household won’'t go hungry for the year and a silver coin to bring prosperity to the household for the new year. The first-foot is supposed to set the luck for the rest of the year. Traditionally, tall dark men are preferred as the first-foot. This stems back to the 4th - 12th century when unwelcome visitors to this shore were Vikings who were short and fair-haired. It is considered luckier to have the opposite type of person to visit. He or she should be honest, healthy, good tempered and liked by all. They must not be carrying a sharp object like a knife. It is not unusual for a household to choose a first footer and make arrangements prior to Hogmanay. Women and red haired people are considered unlucky first footers, as is a person who first foots empty handed with no gift. Such a person will bring bad luck to the household for the rest of the year. Scottish hospitality means that the unlucky first footer cannot be turned away and must come in for some refreshment. Some households overcome this bad luck by asking the person to throw salt on an open fire if they have one or placing a piece of burning straw up the chimney. Roman Catholics will cross themselves if an unlucky first footer arrives at their house. Others make a cross from Rowan twigs and place this at their front door. If an unlucky first footer arrives they touch this twig cross three times saying the name of their God each time before the first footer speaks.

During the day of Hogmanay the household would be busy cleaning so that the New Year could be welcomed into a tidy and neat house. It is considered ill luck to welcome in the New Year in a dirty uncleaned house. Fireplaces would be swept out and polished and some people would read the ashes of the very last fire of the year, to see what the New Year would hold.
Any visitors who arrive before the chimes of midnight on New Year’s Eve would have to be violently shooed away to prevent bad luck. At midnight the man of the house would open the back door to let the old year out and then open the front door of the house to let in the new year.

The etymology of the word Hogmanay is obscure. It may have been introduced to Middle Scots through the Auld Alliance. The most satisfactory explanation is a derivation from the Northern French dialect word hoguinané being derived from 16th century Old French aguillanneuf which is either a gift given at New Year, a children's cry for such a gift or New Year’s Eve itself.

There has always been a strong connection between Scotland and France which dates back to the Auld Alliance between the two countries when they shared a common Queen who was Mary, Queen of Scots. She lived in France for a short time during her childhood and was the Queen of France for a brief period. When she returned to Scotland she introduced many customs to the country and French words to the Scots language.