The Jones family name is a popular Celtic (specifically Welsh) name that originated in the United Kingdom where Jones remains one of the most common surnames. The name Jones was first documented in 1279 in Huntingdonshire England.

In addition to the United Kingdom, Jones is a significantly popular last name in the United States of America.

The Jones family name or surname originated from Celtic heritage, specifically in Wales and then later in England, United Kingdom. Jones is derived from the name "Jon", a medieval variant of John. While Jones was initially a pure Welsh name, various Jones genealogy sources prove that the proximity to England led to a natural immigration of the Jones family name throughout Europe.

Antiquarian John Weston writes, “The forename Johannes was borrowed in the Roman period and became Ieuan in Welsh. This is pronounced something like Y-eye-an. When permanent surnames were adopted in Wales, Ieuan sometimes became Jones and sometimes Evans. A document of 1533 names Thomas ap Ieuan ap David ap Blethyn alias Thomas Jones. In the medieval period, John was borrowed and in time this became used as a surname, sometimes unchanged, sometimes in the style Jones. The forename John is known to have been used in Wales in the thirteenth century."

In 1292, 48 percent of Welsh names were patronymics (a name inherited from a father), and in some parishes over 70 percent. Other names were derived from nicknames, (rarely) occupational names, and a few non-hereditary personal names.

Patronymic names changed from generation to generation, with a person's baptismal name being linked by ap, ab (son of) or ferch (daughter of) to the father's baptismal name to perhaps the seventh generation.

For example, Evan son of Thomas would be known as Evan (ap) Thomas; Evan's son, John would be John (ab) Evan; John's son Rees would be Rees (ap) John; and David's son, James, would be James (ap) David.

Over time, these names would change as "ap [surname]" would become combined. For example, "ap John" (son of John) would become the surname "Upjohn" (ap+John). The most common surnames in modern Wales result from adding an s at the end of the name, as in Jones, Roberts and Edwards. So "ap John" becomes "Johns" or "Jones".

In 1536, the Acts of Union legislation began enforcing common registration of legal documents such as marriage, baptism, and burial. In conjunction with the introduction of English law, these legal records encouraged the adoption of anglicized surnames rather than the patronymic Welsh system.

As most Welsh surnames, however, are derived from patronymics, and often based on a small set of first names, Welsh communities are full of families bearing the same surnames, but who are completely unrelated.