This chapter addresses the role of personality traits in group decision-making and performance processes. It begins with a review of the history of interaction between group and personality researchers to show that, at one time, the domains went hand in hand. Methodological concerns in the 1950s, however, led group researchers to move away from personality, resulting in a piecemeal approach to personality influences in groups. Following this historical analysis, modern work in conflict, group performance, group decision-making, and group maintenance is reviewed, with a key theme being that although there are few systematic studies of traits in groups, there is quite a bit of isolated work being done. The chapter concludes with a discussion of the barriers to increased collaboration between the two camps, why such collaboration is important for both, and some ideas about what a Person × Situation interaction within a group might reflect.