The Spanish regions of Asturias and Galicia are unique in that country for their Celtic origin. Though long under Spanish domination and influenced by Spanish music, both regions retain Celtic-derived musical traditions. Of the two, Galicia has had the more vibrant Celtic traditions in recent years, though Asturias (and also the Basque Country) share characteristics with other Celtic countries.

The oldest and most well-known form of Galician music is the alalas, a form of chanting that has been associated with Galician nationalism. They share characteristics with Celtic nations as well as Castilian, German, Arab and other Mediterranean-area peoples. Their origin is shrouded in mystery, with some scholars asserting Gregorian chants as a major souce, while others point to Greek or Phoenician rowing songs called alelohuías.

Alalas are arhythmic and based on a single, short theme that repeats the melody, separated by instrumental bagpipes or a cappella vocals. Melodies are based on a continuous drone and are almost always diatonic. Over time, alalas have adapted to include choral polyphony which has added harmony and rhythms (most typically in 2/4 or 3/4 time) to the tradition. The melody is formed by repeating all of its notes. A unique characteristic of alalas is that the first cadence is also the last, and they end in an enlarged coda that fades into a sustained and undefined sound.

Instrumentation is usually nothing more than bagpipes (usually in Bb tonality) and various percussion instruments. The hurdy-gurdy was, until recently, also played.

In the 20th century, a Galician roots revival occurred, led by performers like Faustino Santalices and Perfeuto Feijoo.