Significant growth in the number of English language learners (ELLs) in U.S. schools is anticipated to continue, demanding that educators and evaluators have the skills necessary to distinguishing language difference from disability and provide appropriate services to these students. However, little research exists examining the role of evaluator's cultural competence in evaluating ELLs for special education; furthermore, what does exist shows that many evaluators report low levels of self-efficacy as it relates to assessing ELLs. The first chapter of the dissertation reports on a review of 21 articles conducted to address best practices for evaluating culturally and linguistically diverse (CLD) learners, evaluator self-efficacy, and recommendations for conducting culturally competent assessments and evaluations. The majority of the articles identified in this review focused on recommendations for best practices for conducting evaluations rather than reporting empirical findings related to the topic. Only one study was identified that focused on appropriate training needed by evaluation staff to effectively discriminate between language difference and a disability. Based on the findings of this review, additional research, using a rigorous methodology is needed. Addressing that need, the second chapter reports the results of a study conducted to examine the effectiveness of Project PEAC3E (Preparing Evaluators to Accurately Conduct Culturally Competent Evaluations), a reform-oriented professional development model, using case-based activities designed to increase evaluators' sense of self-efficacy, cultural competence, and the accuracy of evaluator eligibility decisions for English language learners (ELLs). The study found that Project PEAC3E was effective in increasing evaluator self-efficacy.