This chapter explores the contribution made to the modern song by Robert Burns, from his first mention of it in a letter to his correspondent Frances Dunlop, to his versions of the song as published by his collaborators, the editors James Johnson and George Thomson. It discusses the differences between the five extant versions of the song in Burns’s own hand, and compares these to the earlier songs discussed in Chapter 2. It deals both with the tune to which Burns set Auld Lang Syne, and with which his version was first published in 1796, and the different tune that appeared when the song was republished by George Thomson in 1799—the most familiar tune today. The chapter offers a variety of possible explanations for why Thomson changed the tune, including through looking at his correspondence with the two composers he commissioned to arrange Auld Lang Syne, Leopold Koželuch and Ludwig van Beethoven. It discusses various theories on this new tune’s provenance, and its relationship to William Shield’s comic opera Rosina. The chapter concludes by looking at the continuing legacy, into at least the early twentieth century, of the songs that predated Burns’s version, and looks at other songs on “auld lang syne” that were contemporary with Burns’s, including one by Susannah Blamire and one variously attributed to John Skinner and Anna Brown.