Product innovations result frequently from inter-firm cooperation, rather than being developed in “isolation” from single firms. The question is not whether or not companies have to collaborate for innovation, but who is the best partner for innovation. Two opposite points of view exist in past research. In the first, competitors cannot be good partners and companies must focus on non-competitor partners, such as clients, suppliers, or universities. In the second, competitors can be good (even the best) partners, depending on some contingency variables, such as location or company size of the competitor.