<p>Insomnia is a significant public health concern associated with cognitive difficulties and mental health problems. Growing evidence suggests that anxiety and rumination may explain how insomnia contributes to paranoid thoughts. Yet, the specific roles of non-constructive rumination and the distinction between daytime and nighttime insomnia symptoms remain unclear. This study investigated the relationships among insomnia symptoms, anxiety, rumination styles, and paranoid thoughts in adults with and without insomnia. A total of 486 French-speaking participants completed self-report measures assessing insomnia, anxiety, rumination, and paranoid ideation. Network analyses identified the most central symptoms and their associations, and mediation analyses examined whether anxiety and non-constructive rumination explained the link between insomnia and paranoia. Among participants with insomnia, anxiety, non-constructive rumination, and daytime symptoms were strongly connected to paranoid thoughts, and both anxiety and non-constructive rumination partially mediated their relationship, with anxiety showing the strongest influence. However, no causal relationships can be concluded. In contrast, these associations were absent in individuals without insomnia. These findings suggest that daytime symptoms of insomnia may foster paranoid thinking through heightened anxiety and repetitive negative thinking. Understanding these mechanisms highlights the importance of addressing emotional regulation and maladaptive rumination in the treatment of insomnia and related paranoid ideation.</p>