Office for the Suppression of Corruption and Organised Crime

The Office for the Suppression of Corruption and Organised Crime (Ured za suzbijanje korupcije i organiziranog kriminaliteta), better known as USKOK, is a body of the Croatian criminal justice system, attached to the State's Attorney Office and specializing in investigations related to corruption and organized crime.

USKOK was formed in December 2001 and its headquarters are located in Zagreb. The bureau's name is a bacronym from uskok, a term used for a type of Croatian militia men, who fought with guerilla tactics against the Ottoman Empire in the early 16th and 17th centuries.

Since 2009, USKOK has a counterpart in the Criminal Police Directorate (governing the Croatian Police) which has an (intentionally) very similar name – the National Police USKOK (Policijski nacionalni USKOK), as well as in the judiciary – the Court Departments for Criminal Cases in the Jurisdiction of USKOK (Sudski odjeli za postupanje u predmetima kaznenih djela iz nadležnosti USKOK-a). Described as "one of the world's most formidable anti-corruption outfits", the agency has prosecuted 2,000 individuals and achieved a 95% conviction rate (2012), including former Prime Minister Ivo Sanader.

In its 2014 EU Anti-Corruption report, the European Commission commended USKOK's ability to "carry out impartial investigations into allegations of corruption irrespective of the political affiliation or connections of those involved". But in a subsequent report in 2017, the EC noted enduring problems concerning inter-institutional coordination, and called the overall effectiveness of the institutional framework into question.