Lieutenant colonel ( United States ) In the United States Army , Air Force , and Marine Corps , a lieutenant colonel is a field grade military officer rank just above the rank of major and just below the rank of colonel . It is equivalent to the rank of commander in the other uniformed services . The pay grade for the rank of lieutenant colonel is O - 5 . The insignia for the rank consists of a silver oak leaf , with slight stylized differences between the Army / Air Force version and the Navy / Marine Corps version . History . The rank of lieutenant colonel was first created during the Revolutionary War , when the position was held by aides to Regiment Colonel s , and was sometimes known as " Lieutenant to the Colonel . " The rank of Lieutenant Colonel had existed in the British Army since at least the 16th century . During the 19th century , lieutenant colonel was often a terminal rank for many officers , since the rank of " full colonel " was considered extremely prestigious reserved only for the most successful of officers . Upon the outbreak of the Civil War , the rank of Lieutenant Colonel became much more common and was used as a " stepping stone " for officers who commanded small regiments or battalions and were expected , by default , to be promoted to full Colonel once the manpower of a regiment grew in strength . Such was the case of Joshua Lawrence Chamberlain , who commanded a Maine Regiment as both a lieutenant colonel and later as a colonel . After the Civil War ended , those officers remaining in the U . S . armed forces found lieutenant colonel to again be a terminal rank , although many lieutenant colonels were raised to higher positions in a brevet status . Such was the case with George A . Custer , who was a lieutenant colonel in the regular army , but held the brevet rank of major general . The 20th century saw lieutenant colonel in its present day status although , during the 1930s , many officers again found the rank to be terminal as the rank of colonel was reserved for only a select few officers . Such was not the case during World War II , when lieutenant colonel became one of the most commonly held officer ranks in the U . S . Army . Modern usage . In the United States Army , a lieutenant colonel typically commands a battalion - sized unit ( 300 to 1 , 000 soldiers ) , with a Command Sergeant Major as principal NCO adviser . A lieutenant colonel may also serve as a brigade or task force Executive Officer , or principal staff officer , S - 1 ( administration and personnel ) , S - 2 ( intelligence ) , S - 3 ( operations ) , S - 4 ( logistics ) , S - 5 ( civil / military affairs ) , or S - 6 ( computers and communications ) . Usage of " The S - " n " " may refer to either a specific staff section or the staff officer leading a section . Lieutenant Colonels may also be junior staff at a variety of higher echelons . In the United States Air Force , a lieutenant colonel is generally a director of operations or a squadron commander in the operations group , a squadron commander in the mission support and maintenance groups , or a squadron commander or division chief in a medical group . Lieutenant colonels may also serve on general staffs and may be the heads of some wing staff departments . In the 21st century U . S . military , the rank of lieutenant colonel is usually gained after 16 – 22 years of service as an officer . As most officers are eligible to retire after 20 years active service , it is the most common rank at which career officers retire . Rank insignia . The insignia for the rank consists of a silver oak leaf , with slight stylized differences between the Army / Air Force version and the Navy / Marine Corps version . Terminology . While written as " Lt . Colonel " in orders and signature blocks , as a courtesy , lieutenant colonels are addressed simply as " Colonel " verbally and in the salutation of correspondence . The U . S . Army uses the three letter abbreviation " LTC . " The U . S . Air Force and United States Marine Corps use the abbreviations " Lt Col " and " LtCol " ( note the space ) respectively . The U . S . Government Printing Office recommends the abbreviation " LTC " for U . S . Army usage and " Lt . Col . " for Air Force and Marine Corps usage . The Associated Press Stylebook recommends the abbreviation " Lt . Col . " for the Army , Air Force , and Marine Corps . Slang terms for the rank historically used by the U . S . military include " light colonel " , " short colonel " , " light bird " , " half colonel " , " bottlecap colonel " ( referring to the silver oak leaf insignia ) , and " telephone colonel " ( from self - reference as " colonel " when using a telephone ) .