This study examines the influence of corporate governance on the extent of corporate social responsibility and environmental reporting (CSER) in Libyan companies according to legitimacy theory, using quantitative and qualitative methods. The variables used in this study are government ownership, chief executive officer duality, board independence, and board size. The study was conducted in Libya because this country has a unique political and economic system. Moreover, the regime in Libya has influenced the nature of CSER, as has Islamic factor. The quantitative data consist of 162 annual reports derived from 42 Libyan companies. The qualitative data are obtained from 31 financial and information managers from the largest Libyan companies, who expressed their perceptions regarding the influence of the study variables on the extent of CSER. Results confirm that corporate governance generally has no influence on the extent of CSER in Libyan companies, with the exception of board size.