Fannie Fern Phillips was born on September 25, 1867 in Margaretville, Novia Scotia, and later lived in Lynn, Massachusetts. She graduated from Salem Normal School (now Salem State College) in Lynn in 1884, and taught school in Lynn from 1884 until her marriage to Edwin G. Andrews in July 1890. In 1895 and 1896 she attended summer school at Harvard, and earned her BA in 1902 and MA in 1920 from Radcliffe College.
Andrews was deeply interested in education and reform, and in 1905 she formed one of the earliest school-affiliated parents' organizations. In 1907 she founded the Boston Home and School Association, of which she served as Secretary and later President until its closing in 1918.
Prior to World War I, the peace movement actively promoted the role of education in building peace. Andrews, who had been recruited into the movement in 1905 by Lucia Ames Mead, conceived the idea of organizing schoolteachers, and in 1908 founded the American School Peace League (which changed its name to the American School Citizenship League in 1919). She promoted the League to such an extent that support grew rapidly throughout the country. Pacifist literature and study courses produced by the League, much of it written by Andrews, were circulated widely and in 1912 began to be distributed by the U.S. Bureau of Education, with which she was associated until 1921 as a special collaborator. The school essay contests held by the League high school students all over the country participated. Andrews was the League's Secretary from 1908 until her death.
On a trip to Europe in 1910, Andrews promoted the establishment of the School Peace League in Great Britain and Ireland. She was the prime mover for holding the first intergovernmental conference on education (which was to convene at The Hague in Sept. 1914, but could not take place because of the outbreak of war), and for the establishment of the International Bureau of Education.
In 1915, as a founding member of the Woman's Peace Party, Andrews served with Jane Addams as an American member of the International Committee of the International Congress of Women at The Hague and subsequently on the International Committee of Women for Permanent Peace. Andrews also worked for the establishment of the League of Nations as international corresponding secretary of the Central Organisation for a Durable Peace and as a member of the League to Enforce Peace. In 1919, she represented the U.S. Bureau of Education at the Paris Peace Conference. She was appointed by President Roosevelt to serve as a delegate to international conferences on education in 1934 and 1936.
Andrews made substantial scholarly contributions to the study of international relations in her 1917 monograph Freedom of the Seas: The Immunity of Private Property at Sea in Time of War, her 1923 doctoral thesis on the legal aspects of the mandatory system (for which she was awarded a Ph.D. by Radcliffe College), and her 1931 well-received two-volume The Holy Land Under Mandate, based on extensive field research. The latter was widely regarded as the first comprehensive and impartial view of the problems facing the Arabs, Jews and Christians in Palestine under the British Mandate.
Andrews was active in the American Association of University Women, chairing its international relations committee from 1925 to 1932. Her Memory Pages of My Life was published in 1948. She died in Somerville, Massachusetts on January 23, 1950.
The bulk of Andrews' papers are at the Schlesinger Library, Radcliffe College.