Amidst chronic challenges in Inflammatory Bowel Disease (IBD), including physical symptoms, emotional stress, and social constraints, this study aimed to elucidate how patients' perceptions of their illness and its integration into their self-concept are related to their ability to flourish in life. We hypothesized that having a positive and integrative illness identity and social identification will predict higher flourishing, mediated by enhanced health-related quality of life (HRQoL). In an online survey with 244 German-speaking IBD adults (Mage = 36.62, 85% women), we found that lower engulfment (where the disease dominates one's identity) predicted higher levels of flourishing, mediated by higher HRQoL. Enrichment, reflecting personal growth from illness, directly predicted higher flourishing, while stronger social identification predicted higher subjective well-being, but not flourishing. The results highlight the potential of fostering positive illness identities and social connections to enhance flourishing in individuals with IBD or similar chronic conditions.