The Varduli were a pre-Roman tribe settled in the north of the Iberian Peninsula, in what today is the eastern region of the autonomous community of the Basque Country and western Navarre, in northern Spain. Their historical territory corresponds with current Basque-speaking areas, however it is debated whether the Varduli were actually Aquitanians, related to the Vascones, or if they were Celts, related to tribes such as the Cantabri and Celtiberians and which later suffered a Basquisation.
Their ethnonym Varduli is connected with an area that is referred to in documents from the early Middle Ages as Bardulia, which is identified as the cradle of Old Castile. Julio Caro Baroja, a Spanish anthropologist and linguist declared on his works that the term Varduli does not have a Basque origin.
The Varduli are mentioned for the first time during Roman times, by Strabo, who called them Bardyetai, and placed them in the Basque coast, between the Cantabri and Vascones; they are also mentioned by the geographer Ptolemy, who placed them roughly in present-day Gipuzkoa, and by Roman historians, notably Pliny the Elder in his Naturalis Historia, where he reported that Amanum Portus (Roman name: Flaviobriga), present-day Castro Urdiales, was a Varduli city. The Roman geographer Pomponius Mela located them also in the coast, west of the Vascones and east of the Caristii. This lack of agreement about their exact position may have been caused by the continuous movement of the tribes of the northern Iberian Peninsula during events such as the Cantabrian Wars. The first census of the Varduli population took place under the orders of Augustus.