The name Brittney is believed to have its origins in the ancient Celtic language. It is derived from the Old Welsh word "Bryten," which means "Britain" or "land of the Celtic Britons." The name is thought to have emerged in the early medieval period, around the 5th or 6th century AD, when the Celtic tribes inhabited the regions now known as Britain and parts of France.

One of the earliest recorded instances of the name Brittney can be found in the "Annales Cambriae," a medieval chronicle written in Wales in the late 10th century. This text mentions a Welsh prince named "Brittney ap Rhodri," who ruled a kingdom in northern Wales in the late 9th century.

During the Middle Ages, the name Brittney was primarily used by Welsh and Breton families, reflecting their cultural heritage and ties to the Celtic regions of Britain and Brittany in modern-day France. It wasn't until the late 19th and early 20th centuries that the name gained popularity in other parts of the English-speaking world.

Throughout history, there have been several notable individuals named Brittney. One of the earliest was Brittney ap Gruffydd (c. 1062-1137), a Welsh prince and military leader who fought against the Norman conquest of Wales. Another prominent figure was Brittney de Briouze (c. 1130-1199), an Anglo-Norman nobleman and Lord of Briouze in Normandy.

In more recent times, the name Brittney has been associated with several famous individuals, including Brittney Spears (born 1981), the American singer and entertainer, and Brittney Murphy (1977-2009), the American actress and singer.

Other notable individuals named Brittney include Brittney Griner (born 1990), the American professional basketball player, Brittney Reese (born 1986), the American Olympic long jumper, and Brittney Cooper (born 1980), the American author and cultural critic.