<p>This study investigates the influence of overconfidence among Chief Executive Officers (CEOs) and Chief Financial Officers (CFOs) on accounting conservatism through the lens of the false consensus effect. It differentiates between non-discretionary conservatism, which is not attributable to managerial opportunism, and discretionary conservatism, which is subject to managerial judgment. Drawing on a sample of publicly held firms in the United States, the findings indicate that the false consensus effect associated with managerial overconfidence intensifies systematic cognitive bias in non-discretionary conservatism, while diminishing the degree of conservatism in discretionary financial reporting. Collectively, these results underscore the significance of the false consensus effect as a determinant of managerial decision-making processes.</p>