Radio B105 (Brisbane's '#1 Hit' Music Station)

B105 (call sign: 4BBB) is a commercial FM radio station broadcasting on 105.3 MHz in Brisbane, Australia. It is part of the Austereo Radio Network. B105's primary audience is 10 to 24 age group.

The station now known as B105 began life as 4BK, commencing transmission in 1930 on the AM band, initially on the frequency 1290 kHz before changing to 1300 kHz in 1935. The introduction of 9 kHz spacing on the AM band led to 4BK moving to 1296 kHz in 1978.

In 1988, the Austereo group purchased the station from Hoyts, intending to use it as a vehicle to bid for an FM conversion licence. Austereo won the FM licence, and in February 1990, the station changed its callsign to 4BBB (not used on-air, unlike the previous AM callsign) and commenced broadcasting on a frequency of 105.3 MHz with the on-air name B105.

Between March 1990 until 2006 it was the highest rating station in Brisbane, except in one ratings survey in 1994, beaten by AM station 4KQ.