Frankie Armstrong (born 13 January 1941 in Workington, Cumberland, England) is a singer and voice teacher. She has worked as a singer in the folk scene and the women's movement and as a trainer in social and youth work. Involved with folk and political songs from the 1950s, she has performed and/or recorded with Blowzabella, The Orckestra (with Henry Cow and the Mike Westbrook Brass Band), Ken Hyder's Talisker, John Kirkpatrick, Brian Pearson, Leon Rosselson, Dave Van Ronk and Maddy Prior. She is blind from glaucoma.

Frankie Armstrong moved to Hoddesdon, Hertfordshire as a young child. She began singing in a group with her brother singing Elvis Presley and Little Richard numbers, and in 1957 joined the Stort Valley Skiffle Group which a few years later changed its name to the Ceilidh Singers as its repertoire moved towards folk music. The group founded the Hoddesdon Folk Club.

In 1963 she began working with Louis Killen and performing solo, then in 1964 she joined The Critics Group under Ewan MacColl, Peggy Seeger. In 1965 sang at the Edinburgh Festival "Poets In Public", with John Betjeman, Stevie Smith and Ted Hughes. Her first recording, in 1965, was at the invitation of Bert Lloyd who as director of Topic Records was putting together a recording of erotic songs with Anne Briggs, released as The Bird in the Bush.

In the mid-1970s Armstrong pioneered workshops based on traditional styles of singing. She was a member of the Feminist Improvising Group (FIG), co-founded in 1977 by vocalist Maggie Nicols, bassoonist Lindsay Cooper, keyboardist Cathy Williams, cellist and bassist Georgina Born, and trumpeter Corinne Liensol. Armstrong collaborated within the accomplished FIG after 1978, and also with free jazz pianist (and partly percussion playing) Irene Schweizer, saxophonist (and film maker) Sally Potter, trombonist and violist Annemarie Roelofs, flutist and saxophonist Angele Veltmeijer, and saxophonist and guitarist Francoise Dupety.