Captain is the name most often given in English-speaking navies to the rank corresponding to command of the largest ships. The rank is equal to the army rank of colonel and air force rank of group captain.

Equivalent ranks worldwide include ship-of-the-line captain (e.g. France, Argentina, Spain), captain of sea and war (e.g. Brazil, Portugal), captain at sea (e.g. Germany, Netherlands) and "captain of the first rank"