LGA is a three-letter abbreviation with multiple meanings, including:
- Labor-Green Accord, a 1989 political agreement between the Labor and Green parties in Tasmania, Australia
- LaGuardia Airport, IATA code for an airport in New York City, United States
- Land grid array, a physical interface used by some microprocessors
- Landesgewerbeanstalt Bayern, a German certification company
- Lansing Grand River Assembly, a General Motors automobile assembly plant
- Large for gestational age, a term referring to the size of babies
- Lattice gas automaton, a type of cellular automaton
- Liptako-Gourma Authority, a regional development organization in Africa
- Local Government Aid, assistance given to local governments in the United States
- Local Government Area, a type of governmental entity in several countries
- Local Government Association, a body for advancing the interest of local governments in the United Kingdom
- Local Government Authority, in relation with First Nations government in Canada
- London Gatwick Airport, an airport in London, United Kingdom (LGA is an acronym, LGW is the IATA code)
- Low-gain antenna, an antenna with a broad radiowave beam width
- Maltese Lotteries & Gaming Authority (Malta), public authority regulating all gaming in Malta
- Light Green Advisors, specializes in environmental sustainability investments