Findings of 43 studies examining the effects of class placement on social adjustment of mentally retarded students were reviewed. Studies met the following criteria: (1) they investigated the class placement of mentally retarded students; (2) they included a dependent measure of social adjustment; and (3) they reported quantitative tests of placement effects. A comparison of special versus regular class placement revealed significantly better social adjustment in special classes, while comparison of special versus resource classroom placement revealed no difference in overall social adjustment. Ratings by teachers and peers indicated better adjustment for students in special classes while ratings by adults other than teachers tended to indicate superior social adjustment in regular or resource classes. Self reports of social adjustment revealed no placement differences. Policy implications included the importance of considering different perspectives on the issue of social adjustment. (Author/CL)