The Leader of the Opposition (Spanish: Líder de la oposición) is the politician who leads the opposition in Spain. It is an unofficial, mostly conventional title traditionally held by the leader of the largest party in the Congress of Deputies—the lower house of the Spanish parliament, the Cortes Generales—not within the government. In the Congress seating plan, the Leader of the Opposition sits directly across from the Prime Minister. The last undisputed Leader of the Opposition until 1 October 2016 was Pedro Sánchez.