Ethical Culture Fieldston School (ECFS), also known as Fieldston, is a private pre-K–12th grade coeducational school in New York City with two campuses in Manhattan and the Bronx. The school is a member of the Ivy Preparatory School League. The school serves approximately 1,700 students with 480 faculty and staff.

Felix Adler was a German American professor of political and social ethics, rationalist, influential lecturer on euthanasia, religious leader and social reformer who founded the Ethical Culture movement.