This study aims to unearth whether extensive reading can help university students on the development ofvocabulary. Two research groups - the experimental group who has read more materials chosen by the researchers apart fromin-class readings (95 minutes for class activities and 40 minutes for extensive reading) over the period of 10 weeks and thecontrol group who has absorbed classroom activities only - involved in the experiment. The results, which were collectedfrom three methods of test, observation and interview to evaluate the vocabulary gains of the participants, showed that animprovement on vocabulary of the both groups was found but the experimental group performed their use of vocabularyrange in reading, writing, and speaking better than that in the control group.