The lion’s share of policy in the United States is made by administrative agencies. Agencies not only make policy choices, they must also implement policy effectively. Oversight institutions play an integral role in the policymaking process by monitoring, through review of agency policy actions, both policymaking tasks. Through analysis of a formal model I develop a theory of policymaking between agencies and courts and show that review can impact agency effort choices even when bureaucratic subversion is not a concern. At times the court has no impact on this effort and the agency is unconstrained. However, when the agency’s effort dictates whether or not the court defers to the agency’s actions judicial review does affect effort decisions. In this setting, review can either strengthen or, counter-intuitively, weaken agency effort incentives. Implications for executive and congressional oversight are discussed in light of these results.