"Little Willy" is a song written by songwriters Nicky Chinn and Mike Chapman and performed by the British glam rock band The Sweet, released in 1972 as a non-album single in the UK, peaking at number 4 in the UK Singles Chart. It was released in the US in January 1973 and also appeared on their US debut album The Sweet and became their biggest hit in the US, reaching number 3 on the Billboard Hot 100. Billboard ranked it as the number 18 song for 1973.

Sweet is a British glam rock band that rose to prominence in the 1970s. Their best-known line-up consisted of lead vocalist Brian Connolly, bassist Steve Priest, guitarist Andy Scott and drummer Mick Tucker.