Which song is most sung throughout the world?

The most sung song throughout the world is Happy Birthday to You. It is sung by millions of people every year in different countries, languages and cultures. Initially published as a poem in 1893, it became a popular tune around the turn of the 20th century and reached international fame in the 1920s. In the United States, the song is owned by the Warner Chappell Music publishing company and generates 20 million pounds every year for its owners in performance royalties and licensing.