Rosa Smith Eigenmann (October 7, 1858 – January 12, 1947) was an American ichthyologist (the branch of zoology devoted to the study of fish), as well as a writer, editor, former curator at the California Academy of Sciences, and the first librarian of the San Diego Society of Natural History. She "is considered the first woman ichthyologist in the United States." Eigenmann was also the first woman to become president of Indiana University's chapter of Sigma Xi, an honorary science society. She authored twelve published papers of her own between 1880 and 1893, and collaborated with her husband, Carl H. Eigenmann, as "Eigenmann & Eigenmann" on twenty-five additional works between 1888 and 1893. Together, they are credited with describing about 150 species of fishes.