Lemlich was born March 28, 1886, in the Ukrainian city of Gorodok, to a Jewish family. Raised in a predominantly Yiddish-speaking village, young Lemlich learned to read Russian over her parents' objections, sewing buttonholes and writing letters for illiterate neighbors to raise money for her books. After a neighbor introduced her to revolutionary literature, Lemlich became a committed socialist. She immigrated to the United States with her family in 1903, following a pogrom in Kishinev.