Background/Objectives: Diet and mental health constitute two significant modifiable factors affecting Inflammatory Bowel Disease (IBD). The present exploratory study explores potential interrelationships between mental health and eating patterns in IBD patients in Greece. Methods: A mixed-methods approach was followed. Two hundred and eighty-three individuals living with IBD in Greece (n = 110 UC, n = 173 CD) participated in an online questionnaire survey examining demographic characteristics, anxiety, depression, and dietary attitudes. Fourteen semi-structured interviews explored the lived experiences of diet, mental health, and disease among IBD patients. Results: Quantitative study revealed that 45.77% of patients scored above the clinical cutoff for anxiety (GAD-7 ≥ 10) and 48.37% for depression (PHQ-9 ≥ 10). Patients with UC exhibited a significantly higher prevalence of moderate to severe anxiety (54.5% vs. 37.0%, p = 0.004) and depression (54.5% vs. 42.2%, p = 0.042) compared to CD. Disordered eating attitudes were present in 27.22% of the total sample, with no significant differences between diagnostic groups (p = 0.985). Thematic analysis revealed three overarching themes, namely (a) ‘life in two phases: IBD impact on health’, (b) ‘mental health and diet interplay—their perceived impact on IBD’ and (c) ‘coping strategies for managing IBD’. Conclusions: Our findings highlight the dynamic interplay among diet, mental health, and IBD experience. The study underscores the importance of developing holistic biopsychosocial interventions integrating medical, dietary, and psychological components for IBD management.