An American school overseas is concerned with offering equal academic opportunities for the non-native English language learners (ELLs) on campus. It has not been determined if the in-class teaching method or the out-of-class teaching method is more effective. The purpose of this study is to determine if there is a difference in end-of-year achievement between these 2 different methods. Guided by Vygotsky`s theory of cognitive social development and Krashen`s theory of exposure to language, the research question addressed the difference in 3rd through 5th grade students' achievement test scores between the in-class teaching method and the out-of-class teaching method. The causal comparative study compared the standardized Stanford and Northwest Evaluation Association Measures of Academic Proficiency achievement test data from 244 students for 1 year of out-of-class teaching with 3 subsequent years of in-class teaching. The Kruskal-Wallis test indicated a significant difference between the 2 methods (H = 7.88, df = 3, p = .049) only in the 1st year of in-class teaching. As the results are inconclusive, the results of this study were shared with teachers and administrators and a discussion was facilitated about alternatives to the in-class teaching method in order to develop a research-based curriculum that will help ELLs to succeed in the local school.