Frankie Armstrong (born 13 January 1941) is an English 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. Her repertoire ranges from traditional ballads to music-hall and contemporary songs, often focusing on the lives of women.

She is a key mover of the natural voice movement and is the president of the natural voice network, and has been a voice coach for theatrical groups, including at the National Theatre for 18 years. 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.