Coeliac Disease (CD) is a chronic, life-long autoimmune condition, triggered by the ingestion of gluten. The recommended treatment is adherence to a strict gluten-free diet (GFD). However, the presence of a complex bi-directional relationship between adherence and psychosocial experiences has meant CD is commonly associated with reduced quality of life (QoL) and psychological well-being. This thesis aimed to highlight the presence and use of interventions targeting QoL and psychological well-being, within the CD community. Part A of this portfolio presents the first systematic review to synthesise adjunctive interventions beyond a GFD, that focus on improving QoL and psychological well-being in individuals with CD. The review identified seven categories of intervention types with varied effectiveness, quality, and risk of bias. The findings suggest key areas for future research, aligning with the Medical Research Council guidelines. Part B of this portfolio presents an empirical pre-post study on the development and application of an online psychological intervention, based on Cognitive Behavioural Therapy, for adults diagnosed with CD within the last two years. Funded by Coeliac UK, this intervention was developed drawing upon literature, evidence-based models and with Patient and Public Involvement. Results indicated high levels of interest and retention, with qualitative feedback confirming the intervention’s relevance and acceptability. Quantitative data showed significant improvements in QoL, anxiety, depression, GFD adherence and physical symptoms across three time points (pre, post, one month follow-up). The study provided valuable evidence for future research to build upon these results, and for holistic care packages in the community.