Numerous authors, including Isidore of Seville, Julio Caro Baroja, Aureliano Fernández Guerra and Adolf Schulten, have explored the etymology of the name Cantabria, yet its origins remain uncertain. The Online Etymology Dictionary states the root cant- is said to come from the Celtic for “rock” or “rocky”, while -abr was a common suffix used in Celtic regions. Thus, Cantabrian could mean “people who live in the rocks” or “highlanders”, a reference to the steep and mountainous territory of Cantabria.

The name Cantabria could also be related to the Celtic root “kant” or “cant” meaning edge or rim thus “coastal district,” or “corner-land”, “land on the edge” thus having the same probable derivation as the name of the English county of Kent and Canterbury, one of its major cities.

During the Spanish liberal regimes of the 19th century, the term came to be increasingly associated to the province of Santander. However, during the late medieval and Modern Period literature, Cantabria and Cantabrians refer to the Basque Country, especially the lordship of Biscay, and the Basques.