The purpose of this study was to investigate changes of language anxiety in EFL classroom and relation between the change in anxiety and learners’ performance. The participants were 76 first-year non-English majors from various disciplines of a Korean university. Demographic information questionnaire, English performance test, and Foreign Language Classroom Anxiety Scale were administered to the participants at two time points during a 12-week interval. Mean differences of quantitative data from Time 1 and Time 2, effects of gender and self-perceived proficiency level on anxiety, and the relationship between anxiety and performance were statistically analyzed. The results revealed significant decrease in English anxiety over time, significant effect of self-perceived proficiency level on anxiety, and negative correlation between variation of anxiety level and successful performance. This study suggests that reducing learners’ anxiety level might help their language improvement, and self-perceived language proficiency might be correlated to changes in language anxiety in EFL classroom. Possible implications for English instructors and limitations for future research were presented.