Insomnia Disorder (ID) disrupts both nighttime sleep and daytime functioning and is marked by emotion dysregulation and hyperarousal. This study explored whether Imagery Rescripting (IR) could improve emotion regulation and reduce hyperarousal in individuals with ID. Twelve participants, aged between 20 and 35 years old, completed four IR intervention sessions, each involving a neutral baseline, a negative scenario, and a rescripted positive scenario. Both objective and subjective measures of arousal were monitored. Results showed reduced physiological activation during positive compared to negative scenarios. Pre-sleep arousal also decreased over time whereas indicators of trait-like arousal remained stable. A trend toward improved emotion regulation was observed, though limited measurement precision may have hindered detection. These preliminary findings support the potential of IR to reduce hyperarousal and improve emotional functioning in ID, and highlight the importance of future research with larger samples and more precise tools.