In the United States Army and Marine Corps, a battalion aid station is a medical section within a battalion's support company. As such, it is the forwardmost medically staffed treatment location.

During peacetime, it is led by a medical operations officer, a first lieutenant in the Army Medical Service Corps or a lieutenant from the Navy Medical Corps. During combat, a commissioned medical doctor with the Army Medical Corps may assume leadership of the platoon and direct medical operations. However, in the Army, the medical service officer normally retains control of training, planning, and administration of the platoon while the doctor in charge directs medical care. The primary mission of the battalion aid station is to collect the sick and wounded from the battalion and stabilize the patients' condition.

The battalion aid station belongs to, and is an organic component of, the unit it supports. It may be split into two functional units for up to 24 hours, the main aid station consists of a medical doctor and three 68W combat medics or 8404 corpsmen and a forward aid station consisting of a physician assistant and three more 68Ws or corpsmen. This allows the section to support more than one unit or care as the unit advances or withdraws.

According to the Geneva Convention, military medical facilities, equipment and personnel are non-combatants and may not be attacked as long as they remain in a non combatant role. Medical personnel are allowed weapons for the purpose of self- and patient-defense.