Assessments in English that are constructed for native English speakers may not provide valid inferences about the achievement of English language learners (ELLs). The linguistic complexity of the test items that are not related to the content of the assessment may increase the measurement error, thus reducing the reliability of the assessment. Language factors that are not relevant to the content being assessed may also be a source of construct-irrelevant variance and negatively impact the validity of the assessment. More important, the results of these tests used as the criteria for identification and classification of ELL students, particularly those at the lower end of the English proficiency spectrum, may be misleading. Caution must be exercised when the results of these tests are used for special education eligibility, particularly in placing ELL students with lower English language proficiency in the learning/reading disability category. This article discusses psychometric issues in the assessment of English language learners and examines the validity of classifying ELL students, with a focus on the possibility of misclassifying ELL students as students with learning disabilities.