There is mounting evidence that effective top management teams engage in cognitive conflict but limit affective conflict. Cognitive conflict is task-oriented disagreement arising from differences in perspective. Affective conflict is individual-oriented disagreement arising from personal disaffection. This study of 48 TMTs found that team size and openness were positively related to cognitive conflict. While team size was also associated with greater affective conflict, when teams had high levels of mutuality, greater openness led to less affective conflict. The findings have implications for improving strategic decision making through the use of conflict.