The Yale Institute of International Studies was a research institute that was part of Yale University in New Haven, Connecticut. It was founded in 1935 and was led by directors Nicholas J. Spykman and later Frederick S. Dunn, under whom there was also an associate director, William T. R. Fox. The institute was influential in the development of international relations theory; in particular, it was considered a bastion of international relations realism. The institute came to an end in 1951 due to a conflict with the university administration. Dunn and five of his colleagues left Yale and formed a successor organization, the Center of International Studies, at Princeton University that same year.