This study aims to examine the impact of corporate governance on firm performance and whether state ownership alters the relationship of corporate governance with firm performance. Using an Indonesia data set and a composite measure comprising six individual components of corporate governance quality, we reach the following evidence. First, corporate governance quality is positively associated with firm performance, indicating that ameliorating corporate governance can bring benefits to stakeholders. Second, state ownership is positively related to firm performance, demonstrating that governmental support in developing countries is beneficial to firm growth. Finally, state ownership negatively moderates the effect of corporate governance quality on firm performance, showing that improving corporate governance on state-owned firms is less effective in terms of performance improvement. Such a result may imply that business operations in state-owned companies are more bureaucratic or human-driven.