The purpose of this study was to investigate the incremental validity of work engagement over the proactive personality in predicting proactive behavior at work. Thus, it was tested the extent to which work engagement with its dimensions - dedication, absorption, vigor - can predict the proactive behavior at the workplace over the proactive personality. The data was collected through an online questionnaire and the application was made on a sample of 120 participants who were currently working in an organization, student association, or non-governamental organization. The results of the research have shown that work engagement is a predictor of the criterion in the incremental validity model, although, only absorption of all three dimensions has proved to be a statistically significant unic predictor. Theoretical and practical implication will be discussed.