When students labeled English Learners (ELs) are reclassified as Fluent English Proficient, changes often occur in services and settings (e.g., changes in teachers, peers, and ancillary services). Policymakers play an important role in the reclassification process because they establish test‐based criteria that an EL must attain in order to become reclassified. If the criteria established by policymakers are incongruent with the instructional changes that result from reclassification, then services and settings may be denied to students who would otherwise benefit from them. In response to teachers’ and administrators’ concerns that some ELs who were reclassified were not succeeding without additional supports, California policymakers in 2006 to 2007 changed the reclassification criteria. In this paper, we examine the effects of changing these criteria using data on Latino/a students from the Los Angeles Unified School District, the U.S. district serving the largest number of ELs. Using “difference‐in‐regression‐discontinuities” approaches, we find consistent evidence that this policy change, which increased the difficulty of attaining the test‐based criteria for EL reclassification eligibility, had significant effects on high‐school students’ subsequent English language arts achievement (0.18 SDs) and graduation outcomes (11 percentage points). Specifically, when the criteria for reclassification were lower, students experienced negative effects of reclassification; but when the criteria were raised, students no longer experienced these negative effects. Highlighting the complex interplay between assessments, instruction, and policy, these findings demonstrate the important role policymakers play in the academic success of ELs and speak to policymaker considerations when implementing assessment and accountability systems.