Lieutenant^{[nb 1]} (abbreviatedLt,LT (U.S.),LT(USN),Lieut andLEUT, depending on nation) is acommissioned officer rank in many English-speaking nations'navies andcoast guards. It is typically the most senior ofjunior officer ranks. In most navies, the rank's insignia may consist of two medium gold braid stripes, the uppermost stripe featuring anexecutive curl in manyCommonwealth of Nations; or three stripes of equal or unequal width.

The now immediately senior rank oflieutenant commander was formerly a senior naval lieutenant rank. Many navies also use a subordinate rank ofsub-lieutenant. The appointment of "first lieutenant" in many navies is held by a senior lieutenant.

This naval lieutenant ranks higher than anarmy lieutenants; withinNATO countries the naval rank of lieutenant is aOF-2 and is the equivalent rank of anarmy captain. Other nations will use a navallieutenant rank equivalent to an army lieutenant.

From at least 1580,^[1] the lieutenant on a ship had been the officer immediately subordinate to the captain. Before theEnglish Restoration, lieutenants were appointed by their captains, and this inevitably led to abuses and to the widespread appointment of men of insufficient qualification. In 1677,Samuel Pepys, while he wasChief Secretary to the Admiralty, introduced the first examination for lieutenant,^[2] and thereafter their seniority was dated from the passing of this examination.

A lieutenant was numbered by his seniority within the ship on which he served, so that a frigate (which was entitled to three) would have a first, a second, and a third lieutenant. Afirst-rate ship was entitled to six, and they were numbered accordingly. At first, a lieutenant's commission was given only for the particular ship in which he served, but after the loss ofHMSWager in 1741 and thesubsequent mutiny, theRoyal Navy changed its policy and lieutenants were given more general commissions upon passing their examination.^[1]

During the early days of the naval rank, some lieutenants could be very junior indeed, while others could be on the cusp of promotion to captain; those lieutenants ranged across present-day army ranks from a second lieutenant through to a lieutenant colonel. As the rank structure of navies stabilized, and the ranks of commander, lieutenant commander, and sub-lieutenant (or lieutenant, junior grade in the U.S. services) were introduced, the rank of naval lieutenant became less wide-ranging and is today the equivalent of an army captain.

In theUnited States Navy, promotion to lieutenant is governed byUnited States Department of Defense policies derived from theDefense Officer Personnel Management Act (DOPMA) of 1980. TheUnited States Coast Guard follows the same policy regarding promotion to lieutenant. DOPMA guidelines suggest that at least 95% oflieutenants (junior grade) should be promoted to lieutenant after serving a minimum of two years at the lower rank.^[3]

In theRoyal Navy, promotion to lieutenant is done in line with seniority. Officers are typically promoted after serving as asub-lieutenants (OF-1) for 30 months.^[4] However, promotion may be quicker if a candidate has previous naval service and commissions from the ranks (upper yardsman/senior upper yardsman).^[5]

Thefirst lieutenant (1st Lt or 1LT) in theRoyal Navy and other Commonwealth navies, is a post or appointment, rather than a rank. Historically, the lieutenants in a ship were ranked in accordance with seniority, with the most senior being termed the first lieutenant and acting as thesecond-in-command. Although lieutenants are no longer numbered by seniority, the post of "first lieutenant" remains.

In minor war vessels,destroyers andfrigates, the first lieutenant (either a lieutenant or lieutenant commander) is second in command,executive officer (XO) and head of the executive branch; in larger ships, where a commander of the warfare specialisation is appointed as the executive officer, a first lieutenant (normally a lieutenant commander) is appointed as his deputy. The post of first lieutenant in ashore establishment carries a similar responsibility to that of the first lieutenant of acapital ship.

In the U.S. Navy or U.S. Coast Guard, the billet of first lieutenant describes the officer in charge of thedeck department or division, depending on the size of the ship. In smaller ships that have only a single deck division, the billet is typically filled by an ensign; while in larger ships, with a deck department consisting of multiple subordinate divisions, the billet may be filled by a lieutenant commander. On submarines and smaller Coast Guard cutters, the billet of first lieutenant may be filled by apetty officer.

The insignia of a lieutenant in many navies, including the Royal Navy,^[6] consists of two mediumgold braid stripes (top stripe with loop) on anavy blue or black background. This pattern was copied by the United States Navy, the United States Coast Guard,United States Public Health Service (USPHS) Commissioned Corps theNational Oceanographic and Atmospheric Administration Commissioned Officer Corps (NOAA Corps), and variousair forces (primarily those of the United Kingdom,British Commonwealth, and nations formerly aligned with the Crown) for their equivalent ranks and grades, except that the executive curl is removed (seeflight lieutenant).

In the United States, contingent on the type of uniform worn, U.S. Navy, U.S. Coast Guard, USPHS Commissioned Corps, and NOAA Corps lieutenants also wear pin-on metal collar, shoulder, or headgear insignia, or cloth shoulder, collar, tabbed, or headgear insignia identical to that of aUnited States Marine Corpscaptain and similar to that of aUnited States Army,United States Air Force, orUnited States Space Force captain.

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  Lieutenant
  (Antigua and Barbuda Coast Guard)^[7]
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  Lieutenant
  (Royal Australian Navy)^[8]
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  Lieutenant
  (Royal Bahamas Defence Force)^[9]
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  Lieutenant
  (Bangladesh Navy)^[10]
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  Lieutenant
  (Barbados Coast Guard)
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  Lieutenant
  (Belize Coast Guard)
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  Leftenan
  (Royal Brunei Navy)^[11]
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  Lieutenant
  (French:Lieutenant de vaisseau)
  (Royal Canadian Navy)^[12]
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  Lieutenant
  (Republic of Fiji Navy)
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  Lieutenant
  (Gambian Navy)
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  Lieutenant
  (Ghana Navy)
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  Lieutenant
  (Guyana Coast Guard)
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  Lieutenant
  (Indian Navy)^[13]
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  Lieutenant
  (Irish Naval Service)^[14]
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  Lieutenant
  (Jamaican Coast Guard)^[15]
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  Lieutenant
  (Liberian National Coast Guard)^[16]
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  Leftenan
  (Royal Malaysian Navy)^[17]
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  Lieutenant
  (Namibian Navy)^[18]
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  Lieutenant
  (Royal New Zealand Navy)^[19]
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  Lieutenant
  (Nigerian Navy)^[20]
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  Lieutenant
  (Urdu:لیفٹیننٹ,romanized: Leftinent)
  (Pakistan Navy)^[21]
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  Lieutenant
  (Papua New Guinea Maritime Element)
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  Lieutenant
  (Philippine Navy)
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  Lieutenant
  (Saint Kitts and Nevis Coast Guard)
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  Lieutenant
  (Sierra Leone Navy)
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  Lieutenant
  (South African Navy)^[22]
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  Lieutenant
  (Sri Lanka Navy)^[23]
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  Lieutenant
  (Tanzania Naval Command)
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  Lieutenant
  (Tongan Navy)^[24]
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  Lieutenant
  (Trinidad and Tobago Coast Guard)^[25]
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  Lieutenant
  (Royal Navy)^[26]
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  Lieutenant
  (United States Navy)^[27]
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  Lieutenant
  (United States Coast Guard)^[27]
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  Lieutenant
  (Bislama:Lietnen)
  (Vanuatu Maritime Wing)

• Captain lieutenant
• List of comparative military ranks

• Military ranks of the Royal Navy
• Military ranks of the United States Navy
• Military ranks of the United States Coast Guard
• Naval ranks

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