The aim of the research is to explore the impact of the web-based Leitner Box which is enhanced with social network, particularly Facebook on English vocabulary learning. This research used mixed research design and the data were collected both in qualitative and quantitative ways. The instruments include questionnaire, semi-structured interviews, and performance tests. 35 university’s students were chosen randomly as the respondents for the questionnaire and 30 students from English class were chosen purposively to do the pre-test and post-test. From the findings, it is discovered that students agreed they have problems in learning vocabulary (mean = 3.98). The web-based Leitner Box has a significant positive impact on English vocabulary learning (p<0.05). Findings from the questionnaires also revealed that students gave positive opinions toward web-based Leitner box (mean = 4.28). In term of whether the element of social network can be beneficial to students, the findings showed that social network helps students to learn English vocabulary in this collaborative learning environment (mean = 4.28). The students claimed that web-based Leitner Box and social network make the vocabulary learning process much easier and more interesting by sharing information and actively participating in the collaborative learning environment.
