The growing significance of CSR as a phenomenon within financial economics has raised a fundamental question: does CSR enhance shareholder value or is it an agency cost enjoyed by a firm’s top executives at the expense of stockholders? While a substantial number of studies have examined this question from different perspectives, the evidence continues to be conflicting in nature. In this chapter, we investigate the agency cost and the value-enhancing perspectives of CSR. In particular, we focus on the implications of different corporate governance mechanisms on sustainability and corporate social responsibility. These mechanisms include board monitoring, executive compensation, institutional ownership, accounting and auditing, firm culture, and law and regulations. This chapter attempts to survey and summarize all the relevant studies that explore the relationships between corporate governance mechanisms and corporate sustainability.