The Constitutional Court (Spanish: Tribunal Constitucional) is the supreme interpreter of the Spanish Constitution, with the power to determine the constitutionality of acts and statutes made by any public body, central, regional, or local in Spain. It is defined in Part IX (sections 159 through 165) of the Constitution of Spain, and further governed by Organic Laws 2/1979 (Law of the Constitutional Court of 3 October 1979), 8/1984, 4/1985, 6/1988, 7/1999 and 1/2000. The Court is the "supreme interpreter" of the Constitution, but since the Court is not a part of the Spanish Judiciary, the Supreme Court is the highest court for all judicial matters.

The Court was established along the lines of the Kelsenian model of constitutional justice, also called the European Model because it has been adopted by most European countries. Unlike the main alternative, the American model, the features of the Kelsenian model are that only a constitutional court is empowered to find that a statute is unconstitutional, secondly that of abstract review (that is without requiring legal cases but rather through application by public institutions), and thirdly, that appointments to the court are made largely by political bodies and have limited terms.

The Constitutional Court is authorized to rule on the constitutionality of laws, acts, or regulations set forth by the national or the regional parliaments. The Court has the power to settle conflicts of jurisdiction between the central and the regional governments. Because many of the constitutional provisions pertaining to autonomy questions are ambiguous and sometimes contradictory, it had been suggested from the outset that the Court would play a critical role in Spain's political and social development.

It also may rule on the constitutionality of international treaties before they are ratified, if requested to do so by the Government, the Congress of Deputies, or the Senate.

The abstract review request, that the court determine the constitutionality of a law, can be brought by the Prime Minister, the Ombudsman, fifty members of congress, fifty senators, the executive or parliaments of an Autonomous Community.

In addition, the Court has other powers not typical of the Kelsenian model including determining whether non-legislative acts by the central government, its branches, or the regional governments abide by the distribution of powers defined by the Constitution and other higher laws, hearing complaints from the public about their constitutional rights and preventive review (prior to promulgation) of statutes of autonomy of the regions.

Individual citizens may appeal to the Constitutional Court for protection against governmental acts that violate their "fundamental rights or freedoms". Only individuals directly affected can make this appeal, called a recurso de amparo, and they can do this only after exhausting judicial appeals.

The General Electoral Law of June 1985 additionally allows appeals to this court in cases where electoral boards exclude candidates from the ballot.