Maria (Marika) Sofia Alexandra Stiernstedt, (12 January 1875 – 25 October 1954) was a Swedish author and artist.

She was a socialist despite her background; she came from a baroque aristocratic environment, her father Leonard Wilhelm Stiernstedt was a free lord and her mother Marie Pauline Victoria Ciechanowiecka was a Polish Countess.

Stiernstedt's most famous books are considered to be the novels Fröken Liwin (Miss Liwin), which describes the contradictions between mother and daughter and the problems of aging alone, and Spegling i en skärva (Mirroring in a shard), a selection of short stories Bland människor (About people), and the youth book Ullabella, the portrait book Mest sanning (Most Truth) and the memoir volumes Mitt och de mina and Adjö min gröna ungdom (Goodbye my green youth).

She also made herself known through the publication of various travelogues and newspaper articles Marika Stiernstedt, together with Hjalmar Branting, was among the first to become aware of and report on the Armenian genocide in the Ottoman Empire .

She was awarded the Samfundet De Nio grand prize in 1917 with the then sum of SEK 2,000 and was elected the following year as a member of the society.