Fleet admiral is a five-star flag officer rank in the United States Navy whose rewards uniquely include active duty pay for life. Fleet admiral ranks immediately above admiral and is equivalent to General of the Army and General of the Air Force.

A five-star rank is the highest military rank in many countries. The rank is that of the most senior operational military commanders, and within NATO's standard rank scale it is designated by the code OF-10. Not all armed forces have such a rank, and in those that do the actual insignia of the five-star ranks may not contain five stars. For example: the insignia for the French OF-10 rank maréchal de France contains seven stars; the insignia for the Portuguese marechal contains four gold stars. The stars used on the various Commonwealth of Nations rank insignias are sometimes colloquially referred to as pips, but in fact either are stars of the orders of the Garter, Thistle or Bath or are Eversleigh stars, depending on the wearer's original regiment or corps, and are used in combination with other heraldic items, such as batons, crowns, swords or maple leaves.