The Avery Coonley School (ACS), commonly called Avery Coonley, is an independent, coeducational day school serving academically gifted students in preschool through eighth grade (approximately ages 3 to 14), and is located in Downers Grove, Illinois. The school was founded in 1906 to promote the progressive educational theories developed by John Dewey and other turn-of-the-20th-century philosophers, and was a nationally recognized model for progressive education well into the 1940s.