3LO began transmission in October 1924 as Melbourne's second radio station behind 3AR. The callsign "LO" was taken from a London radio station, 2LO.

In 1932, 3LO and 3AR were among the first twelve radio stations to come under the ABC

In 1942, 3LO and 3AR moved into new broadcast facilities at Broadcast House, Lonsdale Street, Melbourne. The two radio stations would stay there until 1995.

3LO now broadcasts as 774 ABC Melbourne with a mix of local and national news, talkback and current affairs programming. The station now broadcasts from ABC's Southbank headquarters.

See also: List of Australian radio stations