Anna Margaretha "Greta" Donner (née Lyhtberg; 11 February 1726 – 24 September 1774) was a Swedish businessperson.
Born in Visby, Sweden to merchants Mathias Lythberg and Johanna Wihadi, Greta was given a good education and was active as her father's business assistant.
Greta was constantly pregnant during her marriage, giving birth to five children in just six years, although only two of them survived infancy, namely Georg Mathias and Jacob Niclas.
She and her husband settled in Visby on Gotland in 1746; they bought a building, where they founded an empire of import and export with Germany and Great Britain.
The Donner empire expanded under her sons Georg and Jacob, both of whom included their wives in their work, but the business eventually went bankrupt in 1845.