Crooner is a term used to describe primarily male singers who performed using a smooth style made possible by better microphones which picked up quieter sounds and a wider range of frequencies, allowing the singer to access a more dynamic range and perform in a more intimate manner. It is derived from the old verb "to croon" (meaning "to speak or sing softly"). This suggestion of intimacy was supposedly wildly attractive to women, especially younger ones such as teenage girls, known at the time as "bobby soxers". The crooning style developed out of singers who performed with big bands, and reached its height in the 1940s to late 60s.

Crooning is epitomised by jazz vocalists like Bing Crosby and Frank Sinatra, although Sinatra once said that he did not consider himself or Crosby to be "crooners". Other performers, such as Russ Columbo, also rejected the term.