A comptroller (pronounced either the same as controller or as ) is a management-level position responsible for supervising the quality of accounting and financial reporting of an organization. A financial comptroller is a senior-level executive who acts as the head of accounting, and oversees the preparation of financial reports, such as balance sheets and income statements.

In most Commonwealth countries, the comptroller general, auditor general, or comptroller and auditor general is the external auditor of the budget execution of the government and of government-owned companies. Typically, the independent institution headed by the comptroller general is a member of the International Organization of Supreme Audit Institutions. In American government, the comptroller is effectively the chief financial officer of a public body.

In business management, the comptroller is closer to a chief audit executive, holding a senior role in internal audit functions. Generally, the title encompasses a variety of responsibilities, from overseeing accounting and monitoring internal controls to countersigning on expenses and commitments.