Sigþrúður Friðriksdóttir (1830 – 1912) was an Icelandic women's rights activist.
[1] She was married to the high judge Jón Pétursson.
She was one of the co-founders of the women's organization Hið íslenska kvenfélag, which was founded in 1894, and served as its first president in 1894–1897.
She was succeeded by Þorbjörg Sveinsdóttir.