We investigate whether a departure from a tax-based accounting system toward the adoption of International Financial Reporting Standards encourages tax noncompliance. We also examine whether such a departure, which weakens book-tax conformity, affects the informativeness of book-tax differences for tax noncompliance. Our evidence suggests that as book-tax conformity decreases, tax noncompliance increases. Although book-tax differences remain informative of tax noncompliance, the informativeness attenuates as book-tax conformity weakens. Additionally, firms with high incentives to inflate book income are more tax compliant than their counterparts after the departure from a tax-based accounting system