Karl Augustus Menninger was an American psychiatrist and a member of the Menninger family of psychiatrists who founded the Menninger Foundation and the Menninger Clinic in Topeka, Kansas.

The Menninger Foundation was founded in 1919 by the Menninger family in Topeka, Kansas. The Menninger Foundation, known locally as Menninger's, consists of a clinic, a sanatorium, and a school of psychiatry, all of which bear the Menninger name. Menninger's consisted of a campus at 5800 S.W. 6th Avenue in Topeka, Kansas which included a pool as well as the other aforementioned buildings. In 2003, the Menninger Clinic moved to Houston. The foundation was started in 1919 by Dr. Charles F. Menninger and his sons, Drs. Karl and William Menninger. It represented the first group psychiatry practice. "We had a vision," Dr. C. F. Menninger said, "of a better kind of medicine and a better kind of world."