Lieutenant commander (United States)

United States Coast Guard Flag of the United States Public Health Service.svg United States Public Health Service Commissioned Corps NOAA Flag.svg NOAA Commissioned Officer Corps United_States_Maritime_Service.jpg US Maritime Service | Non-NATO rank =

Lieutenant commander (LCDR) is considered a junior officer rank in the United States Navy, the United States Coast Guard, the United States Public Health Service Commissioned Corps, and the National Oceanic and Atmospheric Administration Commissioned Officer Corps (NOAA Corps), with the pay grade of O-4 and NATO rank code OF-3. The United States Maritime Services (USMS) - a voluntary training organization of the U.S. Department of Transportation also uses the rank of Lieutenant Commander.

Lieutenant commander ranks above lieutenant and below commander. The rank is also used in the United States Maritime Service. The rank is equivalent to a major in the United States Army, United States Air Force, United States Marine Corps, and United States Space Force. While majors are field grade officers in their services, LCDRs are in the same category as O-1 (ensign) through O-3 (lieutenants) in the nautical services.

When introducing a lieutenant commander, their full rank should always be used; however, in general conversation they are usually called "commander" even though they are not "full" commanders (which is one rank higher). Simply "lieutenant" is never used because it is one rank lower.

Promotion to lieutenant commander in the U.S. Navy is governed by United States Department of Defense policies derived from the Defense Officer Personnel Management Act of 1980. DOPMA guidelines suggest 70-90% of lieutenants should be promoted to lieutenant commander after serving a minimum of three years as lieutenants and after attaining nine to eleven years of cumulative commissioned service.

While lieutenant commander is the U.S. Navy's first commissioned officer rank to be selected by a board, lieutenant commanders are still considered to be junior officers due to their origin as "lieutenant, commanding". This can be seen by lieutenant commanders not wearing the headgear embellishment (colloquially known as "scrambled eggs") on their combination covers.

The U.S. Coast Guard used its own rank system until World War I. In 1916, discontent grew among Coast Guard captains: By law, they ranked below a lieutenant commander in the U.S. Navy despite similar roles and duties. Pursuant to the Appropriations Act of 1918, the Coast Guard adopted the U.S. Navy rank structure to prevent disagreements over seniority.

There are two insignia used by lieutenant commanders. On service khakis and all working uniforms, lieutenant commanders wear a gold oak leaf collar device, similar to the ones worn by majors in the United States Air Force/United States Space Force and United States Army, and identical to that worn by majors in the United States Marine Corps. The Army and US Air & Space Forces oak leaf is a stylized rounded gold leaf that does not represent any individual tree. The naval services version is styled similar to a southern live oak leaf grown in the Naval Live Oaks Reservation in the 19th Century.

In all dress uniforms, they wear sleeve braid or shoulder boards bearing a single gold quarter-inch stripe between two gold half-inch strips (nominal size). In the case of officers of the U.S. Navy, above or inboard of the stripes, they wear their specialty insignia, notably a star for officers of the line, crossed oak leaves for Civil Engineer Corps.

File:US Navy O4 insignia.svg|United States Navy File:USCG O-4 insignia.svg|United States Coast Guard File:US PHS O4 insignia.svg|United States Public Health Service Commissioned Corps File:US NOAA O4 insignia.svg|National Oceanic and Atmospheric Administration Commissioned Officer Corps File:USMS O4 insignia.png|US Maritime Service a voluntary training organization of the US Transportation Department