The name Rory is of Irish Gaelic origin, derived from the old Irish word "Ruaidhrí" or "Ruaidhri," which means "red king" or "king of the red people." This name has been in use since ancient times in Ireland and Scotland.

The name is believed to have originated in the 6th century CE when it was first recorded as the name of an Irish king, Rory O'Conor, who ruled from 1166 to 1198 CE. He was the last High King of Ireland before the Norman invasion.

In ancient Irish mythology, Rory is also the name of a legendary hero and warrior who was said to have fought against the invading Milesians. This mythological figure is mentioned in several Irish folktales and legends.

The earliest recorded use of the name Rory can be found in the Annals of Ulster, a chronicle of medieval Irish history, where it appears as the name of several Irish kings and noblemen from the 6th to the 12th centuries.

Throughout history, there have been several notable individuals named Rory, including Rory O'More (c. 1620–1655), an Irish rebel leader who fought against the English during the Irish Confederate Wars; Rory Gallagher (1948–1995), an Irish blues and rock musician; and Rory McIlroy (born 1989), a professional golfer from Northern Ireland who has won several major championships.

Other famous individuals with the name Rory include Rory Bremner (born 1961), a Scottish comedian and impressionist; Rory Cochrane (born 1972), an American actor known for his roles in films like "Dazed and Confused" and "Empire Records"; and Rory Underwood (born 1963), a former English rugby union player.