The Ministry of Justice (MJUS) was the department of the Government of Spain responsible for preparing and carrying out the government policy in order to bring the legal system off, specially in criminal, civil, commercial and procedural law affairs, supporting the Administration of Justice and the legal and international cooperation.

Likewise, it was responsible for processing the documents relative to grace right, titles of nobility and Grandees which resolution is given by the King and is carried out by the Council of Ministers, giving legal attendance to the State administrations and it is the communication channel of the Government with the Administration of Justice, with the General Council of the Judiciary and with the Prosecution Ministry, through the Prosecutor General, as well as with the governing bodies of the autonomous communities with judicial responsibilities, the Spanish Data Protection Agency and the associations of legal experts.

The MJUS was headed by the Minister of Justice, who is appointed by the King of Spain at request of the Prime Minister, after hearing the Council of Ministers. The Minister is assisted by three main officials, the Secretary of State for Justice, the Under Secretary of Justice and the Secretary-General for Innovation and Quality of the Public Justice Service. The Solicitor General depends from the Minister.

The ministry had its headquarters in the Palace of the Marchioness of Sonora, Madrid.

The administration of justice was a real prerogative and would continue being it until the 19th century, with the firsts constitutions. However, the monarchs already delegate its judicial powers on civil servants in charge of administering justice but the first time that a kind-of government department was created for judicial affairs was in 1705. That year, King Philip V split the Secretariat of the Universal Dispatch into two secretariats, one for War and Treasury and other «for everything else», which primarily included justice and religion affairs.

However, the true germ of the ministry is found in the Royal Decree of 30 November 1714, which, similar to the French model, divided matters by subject, creating four Secretariats of the Dispatch, among which was the Secretariat of State and of the Dispatch of Ecclesiastical Affairs, Justice and Jurisdiction, in charge of religious affairs, maintenance of royalties from the Crown, the regime of universities, and justice and jurisdiction of Councils and courts, especially in appointments. This secretariat was assumed by Manuel Vadillo Velasco who previously assumed the «Secretariat of the Dispatch for everything else».

This Secretariat of State and of the Dispatch of Ecclesiastical Affairs, Justice and Jurisdiction is renamed Secretariat of the Dispatch of Justice, Political Government and Treasury of Spain and the Indies on 2 April 1717, since it assumes the powers of the Treasury after the General Supervision had been eliminated and after being merged most of the Secretariats of the Dispatch, preserving just three of them. However, this situation will last a short time because in December 1720 the Treasury business regained autonomy, splitting from the Ministry of Justice.

The great reforms carried out by Ferdinand VI in 1754-1755 established the definitive classification of the Secretariats of the Dispatch and their powers. Thus, between 15 May 1754 and 14 May 1755, by a series of Royal Decrees, the Secretariats of the Dispatch become five (the Treasury one is re-created), and they are endowed with a permanent organization. In the case of the Secretariat of Ecclesiastical Affairs, Justice and Jurisdiction, by the Decree of 16 August 1754, its name was changed to the "Secretariat of State and of the Dispatch of Grace and Justice". The subsequent reform of the year 1787 gave rise to a further division of the Secretariats, as a solution to the accumulation of affairs and businesses from the Indies.