This chapter examines how board composition and structure, particularly size, independence, committees, and diversity, influence board effectiveness. It highlights the trade-offs between small and large boards, noting that while smaller boards promote cohesion and accountability, larger boards provide broader expertise and stronger stakeholder connections. Board independence is presented as a cornerstone of good governance, with independent directors playing a critical role in oversight and transparency. The chapter also emphasizes the importance of board committees in enhancing efficiency and specialization, and discusses how diversity, especially in terms of gender and age, can enrich board deliberation but also introduce challenges that require thoughtful management.