For the film, see Rock-A-Bye Baby (film). For the children's musical group, see Rockabye Baby! For the mixtape by Cassie, see RockaByeBaby. 'Rock-a-bye Baby' is a nursery rhyme and lullaby. The melody is a variant of the English satirical ballad Lillibullero. It has a Roud Folk Song Index number of 2768. Rock-a-bye Baby is one of the oldest nursery rhyme songs, translated across hundreds of generations, explaining why the second verse is in the treetop.