The effectiveness of group sandtray therapy, a model of play therapy, was evaluated using a pretest-posttest control group design with 56 preadolescents exhibiting behavioral difficulties. The experimental group (n = 28) received sandtray therapy in small groups for 10 weeks while the wait-list control group (n = 28) received no treatment. Results from the Behavior Assessment System for Children showed statistically significant differences as rated by teachers in total, externalizing, and internalizing behaviors for sandtray participants compared to controls, and participants' parents rated sandtray participants significantly different on externalizing behaviors. Group members' self-reports of symptoms yielded no statistically significant differences. (Contains 2 tables.) [This research was partially funded by the Association for Specialists in Group Work and the Texas Association for Play Therapy.]