William E. May, better known as Billy May (10 November, 1916 - 22 January, 2004) was a United States composer, arranger and musician.

May was born in Pittsburgh, Pennsylvania. He played trumpet professionally in big bands such as those of Charlie Barnet starting in 1939, but became best known as a talented arranger. His arrangement of the Ray Noble composition Cherokee became a major hit of the swing music era.

May worked as an arranger for the bands of Glenn Miller and Les Brown before being hired as staff arranger first for the National Broadcasting Company radio network, then for Capitol Records. At Capitol his studio big band accompanied such artists as Frank Sinatra and Bing Crosby, producing many hit records.

Billy May died of heart failure at the age of 87 in his home in San Juan Capistrano, California.