RGA may refer to:
Companies and organizations R/GA, an international advertising agency Reinsurance Group of America, a reinsurance company Restricted Growth Association, a UK charity that supports people with dwarfism Rezerva generală a aviației (General Aviation Reserve), a Romanian aircraft factory (1916–1919) Roller Girls of the Apocalypse, a roller derby league in Kaiserslautern, Germany Royal Garrison Artillery, a pre-1930 corps of the British Army
Politics Red-Green Alliance (Denmark), a far left-wing political party Republican Governors Association, a US political support organization
Science and technology Regenerative amplification, a process of amplifying laser pulses with a resonator Relative gain array, a tool to determine optimal input-output pairings for MIMO systems Residual gas analyzer, a small mass spectrometer
Other uses IATA code for Hermes Quijada International Airport in Argentina Reallexikon der Germanischen Altertumskunde, a German-language encyclopedia of the history of the Germanic peoples Renzo Gracie Academy, a martial arts school Return goods authorization, part of the process of returning a product to its supplier for repair or replacement