Elorrio is a town and a municipality located in the eastern part of the province of Biscay, in the Basque Country, in northern Spain.

The Argiñeta tombs that today lie just outside the town of Elorrio are both pre-Christian and Christian (the earliest date of the latter is recorded as 893).

In 1053, the San Agustín de Etxebarria monastery was founded, which in time was renovated and eventually became present-day church (an example of Gothic architecture).

In 1468 the town was the site of a major battle between warring clan factions in the Basque Country (the Oñacinos and the Gamboinos).

However, incidents of this type decreased, and between the sixteenth and the eighteenth centuries, the town's fortunes grew, gaining renown for its iron-forges, and especially the production of lances.

In the nineteenth and early twentieth centuries, Elorrio, although it remained a predominantly rural town, became a tourist destination, as people visited the locality to attend one of its two well-known spas.

After the Spanish Civil War, Elorrio went through a period of industrialization, with a number of small, family firms and worker cooperative enterprises emerging.