"Making the Grade: Online Education in the United States, 2006" represents the fourth annual report on the state of online learning in U.S. higher education. This year's study, like those for the previous three years, is aimed at answering some of the fundamental questions about the nature and extent of online education. Supported by the Alfred P. Sloan Foundation and based on responses from over 2,200 colleges and universities, the study addresses the following key questions: (1) Has the growth in online enrollments begun to plateau?; (2) Who offers online courses and programs?; (3) Is online education becoming part of long-term strategy for most schools?; (4) How do Chief Academic Officers rate the quality of online courses?; and (5) What barriers do academic leaders see to widespread adoption of online learning? Additional tables are appended.