Lydia "Lizzie" Burns (6 August 1827[2] – 12 September 1878) was a working-class Irish woman, the wife of German philosopher Friedrich Engels.

[1] Lizzie had an elder sister, Mary (1821–1863), a lifelong partner of Engels's until her sudden death of a heart disease.

[1] Eleanor Marx wrote that[8] [Lizzie] was illiterate and could not read or write but she was true, honest and in some ways as fine-souled a woman as you could meet.Rachel Holmes notes that "Like her sister, Lizzie Burns was a dedicated player in the Irish Republican movement, and the house she shared with Engels at 86 Mornington Street was a meeting place and a safe house for Fenian activists.

In early September 1878, Burns fell seriously ill with some kind of tumor,[1] and to please her religious beliefs, Engels married her.

He later wrote about her:[3] My wife was a real child of the Irish proletariat and her passionate devotion to the class in which she was born was worth much more to me – and helped me more in times of stress – than all the elegance of an educated, artistic middle-class bluestocking.Engels had Lydia buried at St Mary's Catholic Cemetery, Kensal Green and wrote on the gravestone: ″LYDIA, Wife of Frederick Engels".