Technical Sergeant, commonly shortened to "Tech Sergeant" in a somewhat informal parlance, is the sixth enlisted rank (pay grade E-6) in the U.S. Air Force, just above staff sergeant and below master sergeant. A technical sergeant is a noncommissioned officer and abbreviated as TSgt (with no period in official USAF and other military correspondence). Official terms of address are "Technical Sergeant" or "Sergeant", although many use "Tech Sergeant".
Within Air Force enlisted ranks, promotion to technical sergeant has historically been the second-most difficult rank to achieve (only the rank of senior master sergeant, capped by federal law, has lower promotion rates) and is the most difficult promotion that most career Air Force members achieve. A staff sergeant must have served at least 23 months in grade to be considered for promotion to technical sergeant. It normally takes 10–12 total years of service to attain this pay grade. Technical sergeants mentor junior enlisted personnel while preparing themselves for promotion to master sergeant, the entry rank of the senior non-commissioned grades.
Technical sergeant was a rank in the United States Marine Corps until 1958. From 1941 until 1946, the rank was equivalent to grade 2, ranking with gunnery sergeant and other technical ranks with which it shared its insignia. From 1947 until 1958, the rank was reclassified as E-6 and became the sole rank in this grade. The rank was renamed gunnery sergeant and elevated to E-7 after the reorganization of grades in 1959.