Hispano-Celtic is a term for all forms of Celtic spoken in the Iberian Peninsula before the arrival of the Romans (c. 218 BC, during the Second Punic War). In particular, it includes:

Western Hispano-Celtic continuum hypothesis

Western Hispano-Celtic is a term that has been proposed for a dialect continuum on the western side of the Iberian Peninsula, including Gallaecian in the north, Tartessian in the south (according to Koch, and others in between such as Lusitanian (which has sometimes been labelled "para-Celtic"), west of an imaginary line running north–south between Oviedo and Mérida. According to Koch, the Western Celtic varieties of the Iberian Peninsula share with Celtiberian a sufficient core of distinctive features to justify Hispano-Celtic as a term for a linguistic subfamily, as opposed to a purely-geographical classification. In Naturalis Historia 3.13 (written 77–79 CE), Pliny the Elder says the Celtici of Baetica (now western Andalusia) descended from the Celtiberians of Lusitania since they shared common religions, languages and names for their fortified settlements.

Vettonian-Lusitanian sound changes

As part of the effort to prove the existence of a western Iberian Hispano-Celtic dialect continuum, there have been attempts to differentiate the Vettonian dialect from the neighboring Lusitanian language using the personal names of the Vettones to describe the following sound changes (Proto-Indo-European to Proto-Celtic):

Rejection of the Western Hispano-Celtic continuum hypothesis

The Western-Hispano Celtic continuum hypothesis received little support from linguists, who have widely rejected the Celtic interpretation of the Tartessian inscriptions and who generally have regarded Lusitanian as a non-celtic language. The more generally accepted non-celtic conclusion of Lusitanian studies has been confirmed by analysis of more recently discovered Lusitanian inscriptions, that clearly show that Lusitanian cannot be a celtic language and in fact approaches the Italic languages.