In response to the growing achievement gap between English Learners (ELs) and non-ELs, standards-based instruction and assessment have been promulgated at the state and federal level. Yet, the consequences of standards-based assessment reforms for ELs have rarely been systematically studied. The work reported here represents the initial study of a 4-year research project with the purpose of investigating how the implementation of standards-based performance assessments and related instructional strategies influences the achievement of ELs. In this study, we were specifically interested in identifying the opportunity-to-learn (OTL) variables that positively impact student performance. We also investigated potential differences in the impact of OTL on performance between ELs and non-ELs. Our study suggested that there are several factors contributing to students' performance on the Language Arts Performance Assignment (LAPA). At the student level, the analysis suggested that the greatest contributors to individual students' LAPA scores were performance on the Stanford 9 Language test, ethnicity, gender, and language proficiency status. At the teacher level, we found that content coverage was significantly associated with student performance. The study showed that higher levels of content coverage in both writing and literary analyses were associated with higher performance for all students, including ELs. We also found differential impact of one OTL variable, content coverage-writing, on ELs' performance. This finding indicates that the gap between ELs and non-ELs increases as teacher reports of content coverage-writing increase.