Abstract: The purpose of this research was to determine what effect a challenging 6-day wilderness experience would have on the self-concept, and the knowledge of and attitude toward the environment, of 61 12th-grade students. The experimental and control groups were pre- and posttested with the Tennessee Self-Concept Scale (TSCS), the Coopersmith Self-Esteem Inventory (SEI), and an environmental attitude and knowledge questionnaire. Statistical analyses of the pre- and posttest results indicated a significant increase for the experimental group on 3 of 10 measures of self-concept in the TSCS, on 2 of 5 measures in the SEI, and in environmental knowledge. No change in attitude was found for the participants. The control group did not significantly change their scores on any of the measures. The data indicated that changes in self-concept and environmental knowledge can occur from short-term wilderness experiences. Further research into determining the qualities of programs that are effective in causing positive changes in the participants is recommended.