This research proposes a model to measure the effect of family culture on firm performance in family business retailer-vendor strategic partnerships. Prior research that has contributed to the development of the discourse on family culture, organizational culture, family and relationship value, commitment, and trust will be analyzed. Eight hypotheses are presented, four of which are an extension of prior research. The model ratifies a positive relationship between family culture and performance, especially when considering the successor generation. Since the founders of the firm are the personification of the family culture itself, for this group, family culture does not positively influence performance. The outcome of this research will illustrate not only the effects of family culture in family firms’ performance, but also the impact of relationship and behavioral factors in business.