Flag captain (Swedish: Flaggkapten) was in the Swedish Navy a captain or commander who served as deputy to a fleet commander. During the 1900s, the flag captain served as chief of staff of Flaggen, the staff of the Chief of the Coastal Fleet.

A flag captain was a naval officer in the Swedish Navy holding the rank of captain or commander, appointed as the chief of staff to the 'highest commanding officer.'^[1] If he was a flag officer, the flag captain would carry the flag, designated as the command sign, with the standard prescribed for the 'squadron commander'; otherwise, they would carry the broad pennant (galjadett) designated for the 'department commander'.^[2] According to regulations in force before 1875, a flag captain was an officer of the rank of flag officer or regimental officer, assigned to assist the commander of a fleet consisting of at least six ships of the line, frigates, or battalion of archipelago ships.^[1]

Between 1904 and 2000, the flag captain served as chief of staff of Flaggen, the staff of the Chief of the Coastal Fleet.^[3]