Theodóra Thoroddsen was born and grew up in a well-situated, culturally minded family on Vestlandet and was one of three surviving children of fifteen. She had a good education and acquired popular knowledge as well as knowledge of history and verse. In 1884 she married Skúli Thoroddsen, who subsequently became a prominent member of the Althing (the Icelandic Parliament), moved to Isafjörður, and had thirteen children in the course of twenty-two years.
Her best known work from the period between 1912 and 1943, when she began writing seriously after she was widowed at fifty-two years of age, is Þulur, which was published in 1916 and 1938. Her other better known works are Eins og gengur (SS), 1920, and Ritsafn, 1960. She describes the situation of housewives and the conflict between obligation and the creative urge, and her sympathy with the underprivileged is unmistakeable everywhere in her literary universe.