Born in Austria, she studied art under Lindenschmidt in Munich, and won prize money there that enabled her to travel and study in France with Courtois, Colin and Dagnan-Bouveret. At the Atelier Colarossi in 1881 with Helene SCHJERFBECK, the two friends sought out the right places for 'plein air' social realism, and were attracted to Pont Aven in 1883. Marianne met Adrian STOKES there and married him the following year. Later Schjerfbeck would also follow the Stokes pair to St Ives. In 1891, while staying with the Westlakes at Tregerthen Cottage, Zennor, another guest was the great women's rights campaigner, Millicent G Fawcett, who was visiting from Aldeburgh, Suffolk.

Later, when the Stokes' moved on to London (after 1898), Marianne Stokes gave Alice WESTLAKE's London address for many years as her contact for submissions. Her portrait of John Westlake is in the National Portrait Gallery.  Candlemas Day (1901)  was purchased by the Chantrey Bequest for the nation in 1977. A tapestry, Honour the Women, is in Manchester. Along with Elizabeth Armstrong FORBES, Marianne Stokes was considered in the first line of women painters in England by the turn of the 19th century, and according to Sparrow 'has worked of late in that most stern and stubborn medium, tempera, and small things of hers in various exhibitions attract one always with the desire to know more of her most attractive work.'

The painting lives of Marianne and Adrian Stokes are fully explored in the 2009 publication, Utmost Fidelity, which appeared with the major retrospective of their work mounted simultaneously by Penlee House Gallery, Penzance, and the Royal Cornwall Museum, Truro in that year, within a national touring programme. Magdalen Evans, the author and a descendant of Adrian, presented an illustrated lecture on 'The Portraits of and by Marianne & Adrian Stokes' at the National Portrait Gallery in February, 2010.