An officer of three-star rank is a very senior commander in many of the armed services holding a rank described by the NATO code of OF-8. The term is also used by some armed forces which are not NATO members. Typically, three-star officers hold the rank of vice admiral, lieutenant general, or in the case of those air forces with a separate rank structure, air marshal.
Australian three-star ranks 
- Vice admiral (Royal Australian Navy three-star rank)
- Lieutenant general (Australian Army three-star rank)
- Air marshal (Royal Australian Air Force three-star rank)
Official rank insignia for Australian 'three-star' officers do not use stars in the same fashion as the United States (the RAN does incorporate stars into the hardboard rank insignia for flag-rank officers but this is in conjunction with other devices). Unofficial star rank insignia (such as that worn by Lieutenant General Leahy in the accompanying image) are sometimes worn when serving with (or visiting) other military organisations in order to facilitate equivalent rank recognition.
Bangladesh three-star ranks 
- Inspector General of Police (Bangladesh Police three-star rank)
- Lieutenant general (Bangladesh Army three-star rank)
- Vice admiral (Bangladesh Navy three-star rank)
- Air marshal (Bangladesh Air Force three-star rank)
Canadian three-maple-leaf ranks 
- Vice admiral/vice-amiral (Royal Canadian Navy three-star-equivalent rank)
- Lieutenant-general/lieutenant-général (Canadian Army and Royal Canadian Air Force three-star-equivalent rank)
Three maple leaves appear with St. Edward's crown and crossed sabre and baton.
Prince Charles holds the rank of Vice-Admiral in an honorary capacity.
Indian three-star ranks 
- Commissioner of police (state) or Director general of police or Additional Director General Of Police (Indian Police three-star rank)
- Director general (Indian Intelligence agencies three-star rank)
- Director general (Indian Federal law enforcement agencies three-star rank)
- Director general (Paramilitary forces of India three-star rank)
- Air marshal (Indian Air Force three-star rank)
- Lieutenant general (Indian Army three-star rank)
- Vice admiral (Indian Navy three-star rank)
Pakistan three-star ranks 
- Inspector-general of police (Pakistan Police three-star rank)
- Lieutenant general (Pakistan Army three-star rank)
- Air marshal (Pakistan Air Force three-star rank)
- Vice admiral (Pakistan Navy three-star rank)
United Kingdom three-star ranks 
- Vice admiral (Royal Navy three-star rank)
- Lieutenant general (British Army three-star rank)
- Air marshal (Royal Air Force three-star rank)
United States three-star ranks 
- Vice admiral (United States Navy, Coast Guard, Public Health Service Commissioned Corps and National Oceanic and Atmospheric Administration Commissioned Corps, three-star rank)
- Lieutenant general (United States Army, Marine Corps and Air Force three-star rank)
An Army or Marine Corps lieutenant general typically commands a corps-sized unit (20,000 to 45,000 soldiers), while an Air Force lieutenant general commands a large Numbered Air Force consisting of several wings. Additionally, lieutenant generals of all services serve as high-level staff officers at various major command headquarters and The Pentagon, often as the heads of their departments.
See also