The rank of midshipman is one of the oldest ranks in the Royal Navy. It is the lowest rank of officer (apart from officer cadet), but is technically a rate in that it is not conferred by commission or warrant but by entry in a ship's books, and can be removed summarily. In previous times midshipmen were considered to be of warrant rank.

A Royal Navy midshipman ranks immediately below a Second Lieutenant in the Army or Pilot Officer RAF. His rank insignia is a white patch with a buttonhole and gold button on the collar.

In the United States Navy a midshipman is for all intents and purposes of an officer cadet. His rank insignia is a plain gold anchor worn on the collar.

The word midshipman derives from the part of ship, amidships, which was their station.

See Comparative military ranks