Research has suggested that negative emotions are associated with problematic Internet use. This study investigated the role of metacognitions as a mediator of the relationship between negative emotions and problematic Internet use. A sample of 97 university students completed the following questionnaires: Hospital Anxiety and Depression Scale, Boredom Proneness Scale, Metacognitions Questionnaire 30, and Internet Addiction Test. All dimensions of metacognition were found to be positively and significantly correlated with problematic Internet use. Positive and significant correlations were also observed between problematic Internet use and negative emotions (anxiety, depression and boredom). Structural equation modeling was used to test a mediation model in which negative emotions predicted metacognitions which in turn predicted problematic Internet use. The results supported the hypothesis that the relationship between negative emotions and problematic Internet use is fully mediated by metacognitions, suggesting that metacognitive theory may be relevant to understanding problematic Internet use. The implications of these findings are discussed.