The Herrerian style, or arquitectura herreriana, emerged in Spain during the last third of the 16th century under Philip II, marking the third and final phase of Spanish Renaissance architecture. It represented a departure from earlier ornate styles like Plateresque and even classical Purism, emphasizing extreme austerity and geometric simplicity. The style is named after Juan de Herrera, who reorganized the construction of the Monastery of El Escorial after the death of Juan Bautista de Toledo, establishing the foundational principles. Other key figures include Francisco de Mora, Herrera's disciple. Characterized as estilo desornamentado ("unornamented style"), it features rigorous geometry, mathematical relations between architectural elements, clean volumes, a dominance of solid walls over openings, and an almost complete absence of decoration. This architectural sobriety was also a deliberate response to Protestantism, aligning with the guidelines set by the Council of Trent.

Herrerian buildings are known for their severe horizontality, achieved through symmetrically arranged, often cubic, forms. They commonly feature wooden roofs clad in slate and distinctive lateral towers topped with conical or pyramidal quadrangular spires, known as "Madrid-style spires," which introduce a vertical element and reinforce symmetry. This style rapidly became the official architecture of the Habsburgs, with the immense socio-political impact of El Escorial's construction and Herrera's appointment as Inspector of Monuments significantly aiding its widespread adoption. It spread from the Madrid region throughout Spain and Spanish America, influencing major works such as the Valladolid Cathedral and the Puente de Segovia by Herrera, and the Ducal Palace of Lerma by Mora, which established a new palatial model for the 17th century. While its popularity waned in the 18th and 19th centuries, the Herrerian style experienced a revival in the 20th century, particularly during the dictatorship of Francisco Franco.