This study examined the predictive relationship between ELs' proficiency levels on the Assessing Comprehension and Communication in English State-to-State for ELs 2.0, students' performance on English language arts Georgia Milestones Assessment System, and academic growth on the Measures of Academic Progress. It was comprised of third through fifth grade English Language Learners. The study compared the percentage of English language learner students at each proficiency level, gender, and grade level and their achievement of English language arts on the Georgia Milestones Assessment System and growth from the beginning of the year to the end of the year on Measure of Academic Progress. The study was evaluated by conducting Pearson correlation coefficients, one-way ANOVA, and mediation analysis. Results for this research question indicated a significant positive relationship between academic achievement and academic growth. There was a significant positive relationship between academic achievement and all eight domains of English proficiency. The results indicated as grade level increased, English proficiency increased, and academic growth and achievement decreased. Results for this research question indicated a significant effect on all eight domains of English proficiency. The results indicated academic achievement is not obtained for almost 77% of ELs scoring in the 4.3 – 4.9 English proficiency level. There were significant results for all eight domains of English proficiency and academic achievement. The three domains of speaking, oral, and composite were mediated by academic growth. Keywords: English Language Proficiency; Academic Growth; Academic Achievement Assessments; English Language Learners; ELLs; EL;