Group work literature acknowledges that the group co-leader relationship influences the development of group members and the group as a whole. However, little direction has been offered for supervisors of group co-leaders to facilitate the development of the co-leader relationship. Reis and Shaver's (1988) interpersonal process model of intimacy identifies a sequence of interchanges that contributes to the development of intimacy in significant relationships. This article discusses how the model can be adapted to conceptualize the development of the co-leader relationship and identify potential supervisory interventions. (Contains 1 figure.)