Harriet Newell Haskell (January 14, 1835 – May 6, 1907) was an American educator and administrator from the U.S. state of Maine. She taught from 1855 to 1860 in Waldoboro, Maine and Boston, Massachusetts. From 1860 to 1868, she was a teacher and principal at Castleton Collegiate Seminary, Vermont. Thereafter, for 39 years, she served as principal at Monticello Seminary in Godfrey, Illinois.