In a controlled laboratory experiment the effects of a team development intervention based on the theory of appreciative inquiry was compared with task oriented team development and lectures on group processes, outcomes and performance. 96 undergraduate students in two semesters of an introductory organization behaviour course participated in 4 person teams and had 13 weeks to complete a task worth 25% of each member's final grade. One third of teams received an appreciative inquiry intervention, another third received a task oriented team development intervention and the final third received a lecture on group dynamics (placebo). Pre and post surveys assessed group process and outcomes; project grades were used to assess task performance. ANOVAs and ANCOVAs on each of the process and outcome measures showed groups receiving appreciative inquiry and task oriented team development scored significantly higher than those receiving the placebo on almost all measures, including task performance. Teams receiving task oriented team development scored significantly higher than appreciative inquiry on task performance. Implications for organization development and directions for future research are discussed.