Concern about the quality and safety of health care persists, 10 years after the 1999 Institute of Medicine report To Err is Human. Despite growing awareness of quality and safety risks, and significant efforts to improve, progress is difficult to measure. Hospital leaders, including boards and medical staffs, are accountable to improve care, yet they often address this duty independently. Shared responsibility for quality and patient safety improvement presents unique challenges and unprecedented opportunities for boards and medical staffs. To capitalize on the pressure to improve, both groups may benefit from a better understanding of their synergistic potential. Boards should be educated about the quality of care provided in their institutions and about the challenges of valid measurement and accurate reporting. Boards strengthen their quality oversight capacity by recruiting physicians for vacant board seats. Medical staff members strengthen their role as hospital leaders when they understand the unique duties of the governing board. A quality improvement strategy rooted in synergistic efforts by the board and the medical staff may offer the greatest potential for safer care. Such a mutually advantageous approach requires a clear appreciation of roles and responsibilities and respect for differences. In this article, we review these responsibilities, describe opportunities for boards and medical staffs to collaborate as leaders, and offer recommendations for how boards and medical staff members can address the challenges of shared responsibility for quality of care.