The aim of this research was to find out whether there is a significant correlation between students‟ habit in playing Mobile Legends game and their vocabulary mastery. This research used correlation study, which was used purposive sampling technique to get the sample. The sample of this research were 53 students. This research was conducted at SMP Negeri 2 Purwokerto in academic year 2017/2018. In this research used two instruments, questionnaire and test. Questionnaire used to know the students habit in playing Mobile Legends game and test used to know students‟ ability in mastering vocabulary. Product Moment Correlation was used to know the coefficient of correlation, with r counted was 0.195. The r counted were between 0.00 – 0.199 in very low level correlation. Even though there were correlated, a very low level of correlation did not shows a significant correlation.