This paper examines the impact of tax authority monitoring and enforcement on earnings informativeness. Using a staggered difference-in-differences design, I exploit the introduction of a new tax administration information system as a proxy for increased tax enforcement. The results imply that the informativeness of earnings improves with an increase in tax authority enforcement. Furthermore, I find that these results are concentrated in firms that are tax noncompliant, firms that are profitable and firms that have more severe income diversion and downward earnings manipulation. Additional tests show that tax expenses are more informative when tax enforcement increases. Overall, this study suggests that tax authority oversight engenders a positive effect on earnings informativeness by reducing the noise in earnings signals.