Constance Mabel Winchell (November 2, 1896 – May 23, 1983) was an American librarian. Winchell worked at Columbia University for thirty-eight years before retiring in 1962. She is best remembered for producing the seventh and eighth editions of the Guide to Reference Books. In 1999, American Libraries included Constance Winchell in a list of 100 most influential individuals in the field of library and information science.