A unique governance structure for mutual funds is unitary board—one board overseeing all funds in the entire family. We find strong evidence for unitary board as an effective governance mechanism. Funds with unitary boards are associated with lower fees, are more likely to pass the economies of scale benefits to investors, are less likely to be involved in trading scandals, and rank higher on stewardship. In contrast, funds with larger or more independent boards charge higher fees and rank lower on stewardship. Our findings indicate that unitary boards of small size, rather than independent boards, may be more beneficial to fund shareholders.