The Gürtel case was a major political corruption scandal in Spain that implicated hundreds of officers of the People's Party (PP), Spain's major conservative party, some of whom were subsequently forced to resign or were suspended. The investigation revealed a network of businesspeople and politicians who allegedly exchanged public procurement contracts and other favors for illicit payments, and illegal party funding in regions such as the Community of Madrid and the Valencian Community.

Gürtel is one of the largest corruption scandals in recent European history and was linked to related scandals, such as the Bárcenas case, which received media attention in their own right. The case came to public attention in early 2009, but for the most part, the suspects were not put on trial until October 2016.

The investigative operation was given the name Gürtel in a cryptic reference to one of the principal suspects, Francisco Correa Sánchez (correa, in Spanish, meaning 'belt' in English, translates to Gürtel in German). Correa was a businessman who cultivated links with PP officers. The Spanish police began to investigate his activities in 2007, after a whistle-blower, Ana Garrido Ramos, provided information regarding alleged corruption in the Madrid region.

The accusations included bribery, money laundering, and tax evasion. They implicated a circle of business people led by Correa and politicians from the People's Party, although some of the evidence referred to participants by initials and nicknames, such as "Luis el Cabron". The alleged illicit activities related to party funding and the awarding of contracts by local/regional governments in Valencia, the Community of Madrid, and elsewhere. Early estimates of the loss to public finances amounted to at least €120,000,000, while some of the alleged bribes paid in return were not particularly large (for example, items of luxury clothing).

On 24 May 2018, the Audiencia Nacional, Spain's highest criminal court, found dozens of people, as well as the ruling People's Party, guilty of fraud, money laundering, and illegal kickbacks.

A judicial investigation was started by Baltasar Garzón, the examining magistrate of the Juzgado Central de Instrucción No. 5, the court which investigates the most important criminal cases in Spain, including terrorism, organised crime, and money laundering. Garzón had five suspects, including Correa, detained in February 2009.

Garzón was suspended as a judge in 2010, pending his own trial on a charge of exceeding his authority with regard to a case unrelated to Gürtel (his investigation into Francoist crimes against humanity). This particular suspension was eventually overturned, but it was still in force when, in 2011, Garzón was given another suspension, this time pending trial for having violated lawyer-client privilege in the Gürtel case (he had recorded conversations between detained suspects and their lawyers).

The case was reassigned to Judge Antonio Pedreira Andrade [es]. In the summer of 2011, Pedreira set bail for Correa at €15,000,000, reportedly the second largest figure in Spanish legal history. Correa's legal team appealed, saying that the amount was not based on an objective assessment of their client's wealth, as Correa's access to some accounts had been blocked, and there was uncertainty about how much wealth he held abroad. Correa was released on bail in June 2012, by which time Pedreira, who was suffering from Parkinson's disease, had been replaced by the third judge to handle the case, Pablo Ruz. Ruz reduced the sum required to 200,000 euros, a reduction reflecting not only the accused's perceived ability to pay but also the length of time he had been held on remand, which was approaching the maximum possible under Spanish law.