Kptlt.

Captain lieutenant or captain-lieutenant is a military rank, used in a number of navies worldwide and formerly in the British Army. It is generally equivalent to the Commonwealth or US rank of Captain, and has the NATO rank code of OF-2, though this can vary.

The same rank is used in the navies of Finland (kapteeniluutnantti), Denmark (kaptajnløjtnant) and Norway (kapteinløytnant). The latest revision of the relevant NATO STANAG standardization agreement makes the longstanding courtesy practice of translating the rank into English as "lieutenant commander" for all German, Danish and Norwegian officers of that rank official.

The Norwegian Navy goes a step further in ranking the kapteinløytnant as OF-3 when serving afloat, disregarding the Norwegian national tri-service ranking (which still equates the kapteinløytnant with the Army rank of kaptein).

In the Estonian Navy the similarly sounding rank of kaptenleitnant is an officer rank classified as NATO OF-4, i.e. equal to commander in the Royal Navy and United States Navy. As the commander of the Estonian Navy is a captain, this is the de facto second highest rank in the Estonian Navy.

The French Army of the Ancien Régime used a rank of capitaine-lieutenant very similar to the British one. It was mostly encountered in the Royal Guard (maison militaire du roi), where the king was officially captain of most of the guard companies, but the effective command was in the hands of a captain-lieutenant. D'Artagnan is perhaps the most famous captain-lieutenant in French history, as commander of the first mousquetaire company.

Kapitänleutnant is an OF2 rank equivalent to the Hauptmann (en: Captain) in the German Army and the German Air Force.

In the Royal Netherlands Navy, a kapitein-luitenant ter zee is equivalent to a US Navy or Royal Navy commander (OF-4).

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