The purpose of this longitudinal investigation was to examine the association between emotion regulation and future insomnia (incidence and persistence). DesignA longitudinal study in the general population. MethodsA survey was sent out to 5,000 individuals in the community. To those who returned the baseline questionnaire (n=2,333), two follow-up surveys, 6 and 18months later, were sent out and then completed by 1,887 and 1,795 individuals, respectively. The survey contained information about demographic factors, insomnia symptomatology, the Difficulties in Emotion Regulation Scale, anxiety, and depression. ResultsThe findings suggested that emotion regulation at baseline was not associated with the incidence or persistence of insomnia. Overall, the effect sizes were very small to medium. When examining changes in emotion regulation over time, a different pattern emerged. Partial support was established for the notion that decreases in emotion regulation were related to incident and persistent insomnia, as a decrease in emotion regulation was associated with a higher likelihood of future insomnia. Yet, the effect sizes were very small to small. ConclusionThis study does partly point towards a longitudinal association between emotion dysregulation and insomnia. This might have implications for the conceptualization and management of insomnia as well as for future research.