Special Investigations Unit

Special Investigations Unit or Special Investigation Unit may refer to:


 * Special Investigations Unit (Ontario), a provincial police oversight agency in Canada
 * CNN Special Investigations Unit, an investigative documentary on CNN
 * Halton Regional Police Service's Special Investigations Unit
 * Multnomah County Sheriff's Office's Special Investigations Unit
 * New York State Office of Tax Enforcement's Special Investigations Unit
 * S.I.U. (film), 2011 Korean action film
 * Shelburne Police Service's Special Investigations Unit
 * Toronto Police Service's Special Investigations Unit
 * White House Plumbers, covert White House Special Investigations Unit during the Nixon presidency