In the United States, when English language learners (ELLs) are tested, they are usually tested in English and their limited English proficiency is a potential cause of construct-irrelevant variance. When such irrelevancies affect test scores, inaccurate interpretations of ELLs' knowledge, skills, and abilities may occur. In this article, we review validity issues relevant to the educational assessment of ELLs and discuss methods that can be used to evaluate the degree to which interpretations of their test scores are valid. Our discussion is organized using the five sources of validity evidence promulgated by the "Standards for Educational and Psychological Testing". Technical details for some validation methods are provided. When evaluating the validity of a test for ELLs, the evaluation methods should be selected so that the evidence gathered specifically addresses appropriate test use. Such evaluations should be comprehensive and based on multiple sources of validity evidence. (Contains 1 table, 2 figures and 2 footnotes.)