Group contingencies is a technology for using peers to influence behavioral change through contingencies; the use of contingent interdependent group rewards for specific group behaviors has been of interest to behavioral researchers. To sort out the effects on quiz scores and peer social interaction (PSI) of group contingencies based on academic achievement (an academic contingency) and on social/group process performance (a social contingency), two studies were implemented for 7 months in an eighth grade English class and a sixth grade reading class. The academic (group) contingency, based on individually accountable task achievement, was investigated using a Baseline 1, Task Interdependence, Social Contingency 1, Package (both social and academic group contingency), Social Contingency 2, Baseline 2, Postchecks reversal design, and both no treatment and no contingency control groups. Two students were targeted who were both academically deficient and socially isolated from their peers. Results suggested quiz scores were highest when both social and academic (package) contingency was in effect. PSI for the isolated students improved with each additional contingency, peaked in the Package condition, and was maintained at 6-week followup. In the second experiment, social (group) contingency baseed upon individually accountable demonstration of group process skills was examined as each student in a group session was required to demonstrate specififed social skills. This experiment was evaluated using a Baseline 1, Task Interdependence, Academic Contingency 1, Package, Academic Contingency 2, Baseline 2, Postchecks reversal design and targeted four students who were socially isolated from their peers and/or disruptive in class. The results indicated that not a single intervention improved quiz scores for all students. PSI improved for all students in the no contingencies and the package conditions. There was particularly strong maintenance of improved social functioning at followup. Support was found for the use of group contingencies in improving both academic and social functioning and the Package (both social and academic group contingencies condition) was found to be the most powerful intervention in improving academic and social functioning. (Author/NRB)