Investigator may refer to:
- Clinical investigator, an investigator involved in a medical clinical trial
- Detective, a person who investigates crimes, can be a rank and job in a police department, state or federal employee, or a civilian called a private detective
- Investigator Strait, a body of water lying between Yorke Peninsula, on the Australian mainland, and Kangaroo Island in South Australia
- New investigator, a designation for less experienced researchers
- Principal investigator, the lead scientist for a particular well-defined science project
- Private investigator (P.I.), a person who does not work for the police or government, but who undertakes investigations as a subcontractor
- UN Special Investigator, a United Nations appointee, charged with investigations or auditing in a specific matter
- Ghosthunter, one of other paranormal investigators
- See also