The aim of the present study was to investigate the outcomes of using multiplayer online computer games for the development of English as a foreign language (EFL) skills (reading, writing, listening, speaking). For this purpose, the study employed a repeated measures design. The study was conducted with 13 multiplayer online gamer EFL learners studying at a private university in Turkey. The data were collected through the analysis of the English proficiency levels of the participants via two sample Cambridge Preliminary English Tests before and after a gaming period in which the participants played multiplayer online computer games to improve their EFL skills. The findings revealed that the gaming period resulted in a significant overall development of target language skills. Taken separately, the listening scores and the speaking scores of the participants demonstrated a significant increase, whereas the reading scores and the writing scores did not. Based on the findings, the study provides theoretical implications for researchers and practical implications for EFL teachers.