This paper explores the association among the corporate ownership structure and the quality of managerial voluntary earnings forecasts, and the association of managerial voluntary earnings forecasts and analysts’ earnings forecasts. Following La Porta et al. (1999), we measure the magnitude of agency problem with the deviation of controlling shareholder’s voting rights from cash flow rights. The empirical results show that when the degree of this deviation is smaller, the managerial voluntary earnings forecasts are more accurate. Furthermore, for firms with smaller deviation of voting rights from cash flow rights, the analyst’s average forecast error diminishes more after managers voluntarily declare earnings forecasts.