Protestantism has had a small impact on Spanish life. In the first half of the 16th century, Reformist ideas failed to gain traction in Castile and Aragon. In the second half of the century, the Hispanic Monarchy and the Catholic Church managed to clear the territory from any remaining Protestant hotspot, most notably after the autos-da-fé in Valladolid (1559) and Seville (1560), from then on. 16th-century Inquisition blurred differences between erasmism, iluminismo and protestantism as if they belonged to a common branch.

The Spanish Catholic Church, or Catholic Church in Spain, is part of the Catholic Church under the spiritual leadership of the Pope in Rome, and the Spanish Episcopal Conference.