The name Ashly is an English variant of the surname Ashley, which itself is a habitational name derived from the parish of Ashley in Staffordshire, England. The name Ashley is thought to have originated from the Old English words "æsc" meaning ash tree, and "léah" meaning meadow or clearing, indicating it referred to a clearing or meadow where ash trees grew.

The earliest recorded use of the name Ashley dates back to the Domesday Book of 1086, where it appears as "Asselie" and "Esselie". The first recorded instance of the variant spelling Ashly appears in the 13th century, although it remained relatively uncommon until more recent times.

One of the earliest known bearers of the name Ashly was Sir Robert Ashly, a 14th-century English knight who fought in the Hundred Years' War. Another notable historical figure with this name was Sir Anthony Ashly (c. 1551-1628), an English courtier and member of parliament during the reign of Queen Elizabeth I.

In the 17th century, the Ashly family played a significant role in the English Civil War. Sir Jacob Ashly (1617-1673) was a prominent Parliamentarian commander, while his brother Sir Ralph Ashly (1615-1677) was a Royalist who served as a general in the army of King Charles I.

During the 18th and 19th centuries, several individuals named Ashly made their mark in various fields. Robert Ashly (1736-1808) was an English portrait painter who worked in London, while William James Ashly (1806-1877) was a British writer and journalist known for his works on horticulture.

Other notable bearers of the name Ashly include Sir Thomas Ashly (1867-1952), a British diplomat and colonial administrator who served as Governor of the Bahamas, and Lancelot Ashly (1907-1987), a British actor and playwright who appeared in numerous films and television productions.

While the name Ashly has its roots in England, it has since gained popularity in other English-speaking countries, particularly in the United States and Canada, where it is often used as a feminine given name in its own right, rather than just as a variant of Ashley.