Group psychoeducation formats were evaluated to determine which promoted the greatest learning and retention of therapeutically relevant information in adult clients with mental disorders. Study 1 compared lecture and interactive formats; Study 2 compared two types of interactive formats. Both studies also measured client satisfaction with the groups. Results demonstrated that group formats allowing for interaction among group members promote more learning and retention than lecture formats; this benefit was shown to interact with client functioning level such that high functioning clients learned the most information within unstructured interactive settings. The importance of matching the delivery of group services with client functioning level and difficulties encountered with using self-reported client satisfaction measures as an indicator of group efficacy are discussed. (Contains 1 table and 3 notes.)