LAV or Lav may refer to:
- Luis Antonio Valencia, Manchester United winger
- Light armoured vehicles
- LAV-25, used by the United States Marine Corps
- LAV III, in service with the Canadian and New Zealand armed forces
- HIV (human immunodeficiency virus), formerly also called lymphadenopathy-associated virus (LAV), the virus that causes AIDS
- Local As View, a view-based query answering approach to data integration
- Lavalier microphone
- Load average, the average load or amount of work that a computer system is doing over time
- Lav pivo, a beer brand in Serbia
- The Last American Virgin, a 1982 film
- Leisure activity vehicle, a car classification
- Lav, an alternate name for Lava, a son of the Hindu deity Rama and his wife Sita, whose story is told in the Ramayana
- Lav, translation in some Slavic languages of the name Lev
- Línea Aeropostal Venezolana, an airline of Venezuela
- Líneas de Alta Velocidad, Spanish high-speed railway lines
- Madrid–Seville high-speed rail line
- Madrid-Barcelona high-speed rail line
- Madrid–Valladolid high-speed rail line
- Madrid–Levante high-speed rail line
- Córdoba–Málaga high-speed rail line