Background. An increasing number of students, who is not a native speaker, enroll in health care courses in 'western' country, raised concern regarding potential difficulties associated with English proficiency and academic performance. The authors set out to determine the extent to which the English language proficiency of student who are not native English speakers affect the performance.Summary. Research paper describing language proficiency and medical student performance were identified from Pubmed and ProQuest Education Databases. Thirteen papers were analyzed. There are two phases of education found in papers, undergraduate and postgraduate. Regarding language proficiency, nine papers had English as a second language as variable while the rest using standardized language test. Two studies concluded that the standardized test in language proficiency alone was not sufficient to adequately assess 'a non-native speaker'. Conclusion. There is a clear correlation between language proficiency and medical students performance. Even more, understanding culture is important too. Sensitive issue could arise because of this. Educator should not fear to analyze and judge student performance in the context of English-s peaking statues. Training in social skills might have a good influence in student acquisition of second language.