The Senate (Spanish: Senado) is the upper house of the Cortes Generales, which along with the Congress of Deputies – the lower chamber – comprises the Parliament of the Kingdom of Spain. The Senate meets in the Palace of the Senate in Madrid.

The composition of the Senate is established in Part III of the Spanish Constitution. The Senate is composed of senators, each of whom represents a province, an autonomous city or an autonomous community. Each mainland province, regardless of its population size, is equally represented by four senators; in the insular provinces, the big islands are represented by three senators and the minor islands are represented by a single senator. Likewise, the autonomous cities of Ceuta and Melilla elect two senators each. This direct election results in the election of 208 senators by the citizens. In addition, the regional legislatures also designate their own representatives, one senator for each autonomous community and another for every million residents, resulting in a total of 58 additional senators.

The Spanish Senate is constitutionally described as a territorial chamber. Its powers are similar to those of the Congress of Deputies. However, by virtue of its role as a territorial chamber, it is endowed with exceptional powers such as authorising the Government of the Nation to apply direct rule on a region or to dissolve city councils. The presiding officer of the Senate is the President of the Senate, who is elected by the members thereof.