We examine how the presence of family control affects the manner in which afirm collaborates with its supplier firms. We find that supplier firms that have a family firm as a major customer exhibit higher overall profitability, higher gross margin, more efficient asset management, and longer duration of the relationship than other supplier firms (without a family customer). Using the difference-in-difference approach, we confirm that our results are not driven by family firms’preference for profitable suppliers to begin with. Our findings indicate that family customer firms maintain a generous and cooperative attitude in their relations with supplier firms, the behavior which is consistent with theories regarding family firms in the finance and management literature.