This paper asks whether schools and colleges should be regarded as institutions as well as organizations, and if so what are the implications. Different conceptions of "institution" are examined including an attempt to distinguish "institution" from "organization". It is suggested that institutions are committed to a set of values beyond the transmission of knowledge and skills, as well as to breadth in education and the importance of continuity and a degree of stability. Positive and negative connotations of the idea of institution are briefly reviewed. The discussion is placed in a wider context of the debate about the public realm and its boundaries. Institutional theory is drawn on regarding the interplay between schools and colleges and their environments. Finally there is a brief discussion of the conception of "civic institution", and its implications concerning the ownership of publicly-funded schools and colleges.