The Radcliffe Institute for Advanced Study at Harvard is an educational institution in Cambridge, Massachusetts, one of the semiautonomous components of Harvard University. It is heir to the name and buildings of Radcliffe College, but unlike that historical institution, its focus is directed not at undergraduate education but postgraduate research.

The Institute came into being by the agreement of October 1, 1999, under which Radcliffe College finally merged formally into Harvard University. However, long before this date the focus of Radcliffe had already begun to shift, as undergraduate women had for a half-century taken their classes at Harvard, and for a quarter-century lived integrated in dormitories with Harvard men.

Among the Institute's most well-known features are the Arthur and Elizabeth Schlesinger Library on the History of Women in America and the Radcliffe Institute Fellowship Program, both of which date back to Radcliffe College days.

During the period of transition from College to Institute, Mary Maples Dunn served as interim dean. On January 1 2001, Drew Gilpin Faust became the Institute's first permanent dean; she stepped down in July 2007 to become President of Harvard University.