Using a uniquely national representative dataset of the Korea Labor and Income Panel Study (KLIPS), this study investigates the economic premium to English skills in the context of South Korea as both government and individuals have allocated enormous resources to its proficiency. Based on the human capital theory, this study investigates determinants of English proficiency, examines gender differences in English skills across younger, middle-aged and elder generations, and explores the economic returns of English proficiency for South Korean people. T-tests are run between female and male respondents aged between 15 and 64 to see how gender and age impact language abilities in terms of speaking, reading and writing proficiency; Independent t-tests and logit regressions are conducted to scrutinize factors that contribute to English proficiency; a combination of propensity score matching (PSM) with the difference-in-differences (DID) methodology is employed to explore whether English proficiency pay in South Korea. This study finds that gender, age, and schooling are determinants of English proficiency, and documents gender differences in English across generations. Most importantly, the results indicate positive economic returns to English proficiency in South Korea. The main contribution of this study lies in the examination of the causality of language and economic variables. The findings might be of interest to language and economic policymakers, educational shareholders, researchers of second language acquisition (SLA) and individuals who attempt to invest in human capital skills.