Elin Matilda Elisabet Wägner (May 16, 1882 – January 7, 1949) was a Swedish writer, journalist, feminist, teacher, ecologist and pacifist. She was a member of the Swedish Academy from 1944.

Wägner's books and articles focus on the subjects of women's emancipation, civil rights, votes for women, the peace movement, welfare, and environmental pollution. She is best known for her commitment to the women's suffrage movement in Sweden, Swedish Society for Woman Suffrage, for founding the Swedish organization Rädda Barnen (the Swedish chapter of the International Save the Children Alliance) and for developing the women's citizen school at Fogelstad (where she was also a teacher on civil rights).

Alongside Fredrika Bremer, Wägner is often seen as the most important and influential feminist pioneer in Sweden.