Walter Kollo (28 January 1878 – 30 September 1940) was a German composer of operettas, Possen mit Gesang, and Singspiele as well as popular songs. He was also a conductor and a music publisher.Kollo was born in Neidenburg, East Prussia. His best known work, the operetta Wie einst im Mai (1913), was the basis of a 1917 Sigmund Romberg operetta in America entitled Maytime.