The authors apply the notion of 'we-ness' (the sense of 'togetherness' shared by family members) to the study of New Product Development (NPD). In NPD, 'we-ness' comes to function as the construct through which people share knowledge at the team level, but also between teams and between organizations. The results confirm that the sense of 'we-ness' enhances product performance by increasing knowledge sharing. At the same time, the paper challenges the appropriateness of the team/family metaphor used to refer to the people involved in product development, as this can be counterproductive in NPD, especially when complex decisions have to be made. The authors argue that both teams and families may show a tendency to limit individuality that can affect performance in NPD, although the family metaphor suggests a more flexible and tolerant approach to new ideas. On the one hand, managers must be careful in using family-based metaphors. On the other, approaching product development from the perspective of family relations, also using the tools of Marriage and Family Therapy (MFT), opens up new possibilities for increasing product performance and managing people within teams, between teams, and between organizations.