Booster may refer to: In science and technology:
- Booster (electric power), a motor-generator set used for voltage regulation in direct current electrical power circuits
- Booster dose, or booster shot, in medicine, a vaccination given after a previous vaccination
- Booster rocket used in space flight to provide the main thrust in the initial phase of the rocket's flight
- Booster engine, extra cylinders on a steam locomotive, driving the trailing truck or a tender truck, to give more power on starting
- Explosive booster, a bridge between a low energy explosive and a low sensitivity explosive
- A co-channel repeater in broadcasting, used to improve signal strength
In other uses:
- Booster (sports), a member of a Booster club, which provides support to a school athletic team or other organization
- Booster seat, a type of infant car seat
- A member of an organized shoplifting ring
- A character in the video game Super Mario RPG: Legend of the Seven Stars
