"Merrily We Roll Along" is a song written by Charlie Tobias, Murray Mencher, and Eddie Cantor in 1935, and used in the Warner Bros cartoon Billboard Frolics that same year. It is best known as the theme of Warner Bros.' Merrie Melodies cartoon 'series.
The theme song is later split in half to be used as the opening and closing music respectively for the Looney Tunes CGI theatrical shorts since 2010, beginning with Coyote Falls.
In the 1970s it was adopted by WGN as the theme music to The Ray Rayner Show (Ray Rayner used Warner Brothers cartoons on his show) and in 1995 it was used as the ending theme of The Sylvester and Tweety Mysteries.
The song shares a title with the 1934 play Merrily We Roll Along by George S. Kaufman and Moss Hart, but is unrelated to it.