Sub-lieutenant
（重定向自Sub Lieutenant）
![Unterleutnant of the Volksmarine](/Images/godic/202502/13/GDR_Navy_OF1c_sleeve2031.jpg")
Sub-lieutenant is a junior military officer rank.
In many navies, a sub-lieutenant is a naval commissioned or subordinate officer, ranking below a lieutenant. In the Royal Navy (RN) the rank of sub-lieutenant is equivalent to the rank of lieutenant in the British Army and of flying officer in the Royal Air Force (RAF).