The Special Investigating Unit (SIU) is an independent South African agency established to investigate corruption and maladministration in state institutions.

| Legal Name | Special Investigating Unit |
|---|---|
| Year Founded | 1997 (29 Years Ago) |
| Jurisdiction | South Africa |
| Constituting instrument | Special Investigating Units and Special Tribunals Act No. 74 of 1996 |
| Head | Leonard Lekgetho (appointed September 2026) |
| Headquarters | Rentmeester Building, 74 Watermeyer Street, Meyerspark, Pretoria, Gauteng, South Africa |
| Overseen by | Minister of Justice and Constitutional Development |
| Website |
The SIU was initially established in July 1997 by President Nelson Mandela through Presidential Proclamation R24 of 1997. Its creation was intended to address serious malpractice and maladministration within state institutions, assets, and public funds. Although it was designed as a temporary body, the SIU continued its operations until it was dissolved by a 2001 Constitutional Court ruling. Following legislative amendments to address the Court's concerns, the SIU was re-established.
The SIU's primary role is to conduct investigations into allegations of corruption and maladministration. It is empowered to take civil action to rectify any wrongdoing discovered during its investigations, including recovering financial losses incurred by state institutions. The agency has the authority to subpoena witnesses, access bank statements and cellphone records, conduct searches and seizures, and interrogate witnesses under oath. Any evidence of criminal conduct uncovered during investigations is referred to the National Prosecuting Authority for prosecution.
In 2019, the Special Tribunal was established to handle civil litigation matters arising from SIU investigations, allowing the agency to pursue asset forfeiture cases without resorting to mainstream high courts. This development aimed to streamline the process of addressing corruption-related issues.
As of September 2026, the SIU is led by Leonard Lekgetho. His appointment marks a new phase in the agency's efforts to combat corruption and restore public trust in state institutions. The leadership team also includes various chief officers responsible for operations, finance, stakeholder relations, and legal counsel.
The Special Investigating Unit plays a crucial role in South Africa's fight against corruption and maladministration within state institutions. Through its investigative and civil litigation capabilities, the SIU aims to protect public resources and uphold the integrity of government operations.