Earlier reviews have asserted the superiority of structure versus ambiguity in the practice of group therapy. This review attempts to specify the dimensions that lead to this asserted superiority. The pregroup training literature is reviewed in terms of method and timing of presentation and content of training. A model is proposed that links content and timing with issues in group development Implications for practice and research are noted.The comparative effectiveness of structure versus ambiguity in the practice of group therapy has been a continuing source of debate among mental health professionals. To date, the empirical evidence supports the position that structure in general and pregroup training in particular can have potent effects on group member variables. The practitioner, however, is still left with diverse and often confusing data upon which to make choices; what structure, on which dimensions, delivered in what fashion, by whom, when, and evaluated in what way? The purpose of this article is to review the relevant literature on three of these dimensions of pregroup therapy structured training: (1) the content of the information presented; (2) the methods used to deliver pregroup training; and (3) the timing of the presentation. Suggestions for the practitioner and future research issues also will be presented.