The Chewonki Foundation is a non-profit institution in Wiscasset, Maine, which runs educational programs with an environmental focus.

Founded in 1915 as a summer camp for boys, the Foundation now runs a four-month high school program—Maine Coast Semester at Chewonki, boys and girls summer camp programs, wilderness trips for teenagers and families, an organic farm, traveling natural history programs where non-releasable wildlife are brought to schools and libraries, as well as week-long environmental education programs for school groups around New England.

The Chewonki Foundation is located on a 400-acre (1.6 km2) peninsula between Westport Island and the town of Woolwich.

The foundation is also a steward of the former Debsconeag Lake camps on Fourth Debsconeag Lake, and the owners of the public Big Eddy Campground off the Golden Road.

With their off-site, program-specific properties, Chewonki took possession of several islands in Mid-Coast Maine to keep them available for public access.