Lieutenant (junior grade) (LTJG) is a junior commissioned 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 Corps, with the pay grade of O-2. The rank is also used in the United States Maritime Service and the United States Naval Sea Cadet Corps.
Lieutenant, junior grade ranks above ensign and below lieutenant and is equivalent to a first lieutenant in the other uniformed services (the Army, Marine Corps and Air Force) and sub-lieutenant in the Royal Navy and the navies of many Commonwealth countries.
The time for promotion to LTJG is a minimum of two years after commissioning in the Navy or 18 months in the Coast Guard. Lieutenants, junior grade typically lead petty officers and non-rated personnel, unless assigned to small aircraft or on staff duty. A LTJG's usual shipboard billet is as a Division Officer.
Lieutenant, junior grade is often referred to colloquially as JG ("Jay-Gee"). Prior to March 3, 1883, this rank was known in the Navy as master.
Read more about Lieutenant (junior Grade): Notable LTJGs, Fictional LTJGs