In this study, the relationship between high performance work system (HPWS) and organizational citizenship behavior (OCB) in multinational corporations (MNCs) in Vietnam, a fast-developing country with highly economic growth in Asia, was investigated. Besides, the underlying mechanism of this relationship was also explored. From the social exchange approach, an underlying mediated mechanism of career success in the relationship between HPWS and OCB was hypothesized. Data collected from individual employees working in multinational companies in Vietnam was used to test the hypotheses. The research findings supported the partial mediating role of career success in the positive relationship between HPWS and OCB. In addition, research implications as well as suggestions for future research were also presented.