Extensive reading has been proven effective for the development of EFL reading fluency. While previous studies have investigated the impacts of ER on reading speed, reading comprehension, and vocabulary knowledge, little research has examined its effects on English language skills. This research aimed to determine whether extensive reading enhances the English language proficiency of EFL university students. During the experiment, both the treatment and control groups had 15 100-minute reading sessions, each consisting of 50 minutes of intensive reading. In the second part of the session, the treatment group could freely choose books to read, while the control group continued intensive reading activities. A pre-test and a post-test were used to assess the participants’ language proficiency. The results indicate that the treatment group outperformed the control group. Based on the findings, several implications have been suggested for English language practitioners, especially those seeking methods to help their EFL students develop English language proficiency.