The name Hayley is an English feminine given name derived from the Old English words "hæg" meaning "hay" and "leah" meaning "meadow" or "clearing". It originated as a surname describing someone who lived near a hay meadow or clearing in an area with Germanic linguistic influences.

In its earliest recorded use as a given name, Hayley appeared in the 16th century. One of the earliest known bearers of the name was Hayley Ould, who was born in Lincolnshire, England in 1557. Around this time, the name also surfaced in literature, such as in the 1590 work "The Faerie Queene" by Edmund Spenser.

Over the next few centuries, Hayley remained an uncommon name, but had several notable bearers. In the 18th century, the English poet William Hayley (1745-1820) helped popularize the name. Another famous Hayley from this era was the British adventurer and author Hayley Gaunt (1758-1828), known for her travels in the Middle East.

As the name grew more fashionable in the 19th century, it was borne by figures like the American author Hayley Barker (1828-1892) and the British artist Hayley Lever (1876-1958). The 20th century saw the rise of celebrities such as the American actress Hayley Mills (born 1946) and the British singer Hayley Westenra (born 1987), further boosting the name's popularity.

Other historical individuals named Hayley include the British Quaker minister Hayley Ann Phipps (1644-1717), the English botanist Hayley Katherine Norman (1862-1939), and the Canadian World War I flying ace Hayley Alexander Trefusis (1897-1964). The name has remained consistently used across English-speaking countries over the past few centuries.