In the United States, a water boy or water girl was someone who worked in the field, providing water to farmworkers in the 19th and early 20th centuries. Today, the name is given to those who work on the sidelines at sports events to provide water for athletes. The phrase has also been used to describe diminutive figures who serve another team or person in the business and political worlds, in a slightly derogatory manner.

"Waterboy" is an American traditional folk song. It is built on the call "Water boy, where are you hidin'?" The call is one of several water boy calls in cotton plantation folk tradition.