FM Boosters are auxiliary transmitters for FM stations that help carry the radio signal to a location that cannot be reached by the primary transmitter. Booster stations carry the exact same audio signal as their parent station.

The call sign for a booster station consists of the parent station's call sign, a hyphen, and then a number from 1 to 9. For example, if radio station WAAA has two boosters, they would be designated "WAAA-1" and "WAAA-2".

FM Booster stations are similar to FM Translators except that boosters operate on the same frequency as the parent station, while translators operate on a different frequency.