The central bodies of governance in family businesses are the supervisory board (supervisory council/advisory board) and the family representation (shareholder committee/family council). Their attributes, tasks, and impacts on success have hardly been researched to date. Alexander Koeberle-Schmid analyzes the relationships between the attributes (e.g., size, knowledge, or commitment), the intensive fulfillment of the respective tasks (e.g., control, advice, and ensuring family cohesion), and the market success of the family business for both bodies. The investigation is based on agency theory and the resource-based approach, as well as expert interviews with renowned family businesses. The empirical verification is conducted using a sample of 117 predominantly large German family businesses. The author demonstrates that the supervisory bodies examined fulfill their tasks such as control.