Fifth Column was an all-women experimental post-punk band hailing from Toronto, Canada, active from 1980 until 1995.

The group originally formed as a trio known as Second Unit, featuring G.B. Jones on drums, Kathleen Pirrie Adams on bass, and Janet Martin on guitar. In the fall of 1980, Caroline Azar attended one of their performances and soon after successfully auditioned to become the lead singer. This new lineup debuted as Fifth Column at the end of 1980. Following the release of their 1986 album, G.B. Jones transitioned to guitar, with Beverly Breckenridge joining the band on bass the same year. Over the years, Fifth Column saw a revolving door of second guitarists and primarily male drummers before concluding their run with a final performance in Ottawa in early 1995.

The lineup throughout their active years was as follows: - G.B. Jones: drums, guitar, vocals (1980 - 1995) - Caroline Azar: vocals, organ, guitar (1980 - 1995) - Kathleen Pirrie Adams: bass (1980 - 1982) - Anita Smith: bass (1982 - 1986) - Beverly Breckenridge: bass (1986 - 1995) - Anne McLean: bass (unknown years) - Janet Martin: guitar (1980 - 1985) - Charlotte Briedé: guitar (1985 - 1990) - Unspecified guitarist (1990 - 1992) - Michelle Breslin: guitar (1992 - 1995) - Donna Dresch: guitar (1993) - David Keyes: drums (1989) - Joel Wasson: drums (1990 - 1992) - Don Pyle: drums (1992 - 1993) - Torry Colichio: drums (1993 - 1994) - Luc Menard: drums (1995)

Their debut full-length recording, To Sir With Hate, was a clever play on the theme song from the British film To Sir With Love, originally performed by Lulu. Notably, the track “The Fairview Mall Story” addresses real events surrounding the media's publication of names of men arrested in police stings, which contributed to the rise of the queercore scene. The accompanying music video, directed by filmmaker Steven Rumbelow, juxtaposed 1950s imagery of men cruising in cars and shopping malls with footage of the band and go-go dancer Bruce LaBruce. Another video for the track "Where Are They Now?" was directed by Marc DeGuerre.

Fifth Column's live performances were distinctive, often featuring films projected behind the band and a 'go-go' boy dancer. They frequently collaborated with guest musicians, incorporating instruments such as saxophone, trumpet, flute, and violin into their shows.

Emphasizing their independent spirit, the band self-released their recordings, including their second full-length album, All-Time Queen Of The World. A video for the song "Like This" from this album was directed by Bruce LaBruce. Additionally, Fifth Column contributed to various compilation albums.

In 1992, they released the single "All Women Are Bitches" through K Records. Despite its controversial nature and limited airplay, the song garnered attention from music critic Everett True and was voted "Single Of The Week" by Melody Maker in the UK. It later appeared on their final full-length album, 36-C, also released by K Records. The band's last recording surfaced in 2002, as part of the Fields And Streams compilation from Kill Rock Stars.

The band is featured in the film Fifth Column at the Funnel, directed by Toronto filmmaker John Porter. Members of the most recent lineup, along with several former members, also appeared in G.B. Jones' film The Yo-Yo Gang, for which the band recorded the theme song.

In 2004, the song "All Women Are Bitches" was reimagined by the band Lesbians On Ecstasy on their debut album, as "Bitchsy." The following year, it was remixed and sampled alongside "Bitchsy" by Kids on TV for the compilation album Giggles In The Dark.

Members of Fifth Column have also collaborated with various other musical groups. Caroline Azar has worked with New York's Kickstand, Shadowy Men on a Shadowy Planet, Greek Buck, and Toronto's Hidden Cameras. Beverly Breckenridge was a member of Phono-Comb. G.B. Jones has collaborated with the Italian dark ambient group Mariae Nascenti and was previously part of the synth-punk band Bunny and the Lakers. She currently performs with Opera Arcana.