In Scotland's Hogmanay celebration, the song traditionally sung at midnight is “Auld Lang Syne.”
The song is based on verses written by the Scottish poet Robert Burns in 1788, although Burns drew on older Scottish traditional material. The Scots title means “old long since,” commonly understood in English as a reference to old times or old friendships.
Its melody became widely associated with New Year's celebrations during the nineteenth and twentieth centuries. In Scotland, people often join hands in a circle during the final verse and cross their arms when forming the circle, a custom especially associated with Hogmanay gatherings.
“Auld Lang Syne” is not Scotland's national anthem. It is also sung at farewells, reunions, graduations, and other transitions, so its use at midnight is part of a broader tradition of marking endings and beginnings.