USAR or U.S.A.R. may refer to:

• United Speed Alliance Racing (now Rev-Oil Pro Cup Series), a car racing series in the United States

• United States Army Rangers, the elite light infantry of the United States Army

• United States Army Reserve, the reserve component forces of the United States Army

• University School of Automation & Robotics, Guru Gobind Singh Indraprastha University, Delhi, India

• Urban search and rescue, rescue operations inside structures or other confined spaces

• USA Rugby, the governing body of rugby union in the United States