Forward observers in the U.S. military are artillery observers who carry the Military Occupational Specialty designator of 13F in the United States Army and 0861 in the United States Marine Corps. They are officially called Joint Fire Support Specialists in the U.S. Army and Fire Support Marines in the U.S. Marine Corps. They are colloquially known as FiSTers, regardless of whether they are members of a FiST. The Battalion Fire Support Officer (FSO) is the Officer in Charge of a Battalion Fire Support Element.

Air Naval Gunfire Liaison Company (ANGLICO) is an airborne fire support and liaison unit of the United States Marine Corps. The mission of ANGLICO is "To provide Marine Air-Ground Task Force (MAGTF) Commanders a liaison capability to plan, coordinate, and conduct terminal control of fires in support of joint, allied, and coalition forces. Per this mission statement, ANGLICOs are not designed to support U.S. Marine Corps maneuver elements. Instead, the doctrinal purpose of ANGLICO is to provide fire support and coordination in support of units adjacent to the MAGTF.