While curriculum-based activities are central in the operation of universities, extra-curricular activities are often disregarded. However, recent studies have shown that participating in extra-curricular activities can substantially improve graduate employability. This chapter, therefore, will report a quantitative study that investigated the effectiveness of the development of employability skills for students in Vietnamese universities via extra-curricular activities. Using the experience of 797 students with these activities at two points in time, 2015 and 2019, it was found that the Youth Union and its associates (YUA) frequently organized a diversity of extra-curricular activities to develop employability skills for students. However, differences were observed between the 2015 and 2019 student cohorts in terms of focus of extra-curricular activities organized by the YUA, students’ patterns of participation, their awareness of the importance of extra-curricular activities, and their perception of how participating in these activities would contribute to the development of several employability skills. The chapter discusses important implications for enhancing the effectiveness of developing employability skills for students via ECAs.