“Auld Lang Syne” is the song traditionally sung at midnight on New Year's Eve.
The title is a Scots phrase meaning “old long since,” commonly understood as “for old times' sake.” The familiar lyrics are based mainly on a poem published by Scottish poet Robert Burns in 1788, although Burns drew on older Scots words and songs rather than inventing every line from scratch.
The melody used today became widely associated with the song in the nineteenth century. Its reflective words about friendship, memory, and shared experiences made it suitable for a farewell to the old year, and the custom spread internationally through Scottish communities and popular culture.
People sometimes call it a national anthem of Scotland, but it is not Scotland's official national anthem. It is also sung at reunions, funerals, graduations, and other farewells, so its use is not limited to New Year's Eve.