This article reviews Rosenthal and Jacobson's (1968) seminal study, "Pygmalion in the Classroom" (PC). We consider what preceded PC, the actual study, immediate criticisms of it, Rosenthal's reactions to the criticism, and, importantly, the research that followed PC from 1968 to roughly 1990. Despite critical criticisms of it, we conclude that PC had a tremendous impact because it stimulated researchers to study expectation effects in the classroom that established that some teachers do form and communicate differential expectations to their students and that some students internalise these expectations in ways that manifest in their actual performance. The research that followed PC has yielded rich concepts and findings that are relevant for theory, practice, and social policy.