Trucios-Turtzioz (Turtzioz in Basque; Trucios in Spanish; Trucíos in Cantabrian) is a town and municipality located in the province of Biscay, in the Autonomous Community of Basque Country, northern Spain, surrounded by other municipalities of Biscay and Cantabria. The name comes from a cold water spring, which existed, or still exists, in the center of the town. In Basque, Iturriotz means "cold spring".