This study examines the effect of corporate ownership structure and board size on earnings management for a sample of 30 non-financial firms registered on the Indonesia Stock Exchange from 2013 to 2016. Earnings management is measured by discretionary accruals using Modified Jones Model. The corporate ownership structure is measured with managerial ownership and institutional ownership. This study also uses three control variables: return on assets, financial leverage, and firm size. Using multiple regression analysis, the results show the relationship between board size and earnings management is negatively significant. However, managerial Ownership and Institutional Ownership have no significant effect on earnings management. The findings also reveal that return on assets and firm size has a significant positive effect while financial leverage has a significant negative impact on earnings management.