The focus of this thesis was to explore the role of self-regulation (SR), that is the ability to monitor and regulate emotions and behaviours, in type 1 diabetes (T1D) management and the development of disordered eating behaviours (T1DE) and insulin omission as a method of weight loss (IO) among women with T1D. Researching the relationship between type 1 diabetes and the psychological and social moderating or mediation factors in developing an eating disorder is of high importance as the prevalence of T1DE and IO is up to 60% in women with T1D, and eating disorders in this population are associated with significant long-term morbidity and mortality risks. Moreover, deficits in SR have been identified among individuals with eating disorders such as anorexia nervosa and bulimia nervosa, and other chronic health conditions including asthma. In this thesis the hypothesis that the consistent demand that T1D management has on SR, due to the need to frequently monitor blood glucose readings, calculate carbohydrate consumption and appropriate insulin dosages, results in deficits in SR which increases susceptibility in women with T1D to developing T1DE and IO. Potential moderating or mediating factors were explored, such as the role of carbohydrate counting and food perceptions and social support. Overall, the results from the four studies conducted as part of this thesis provide evidence for the role of SR deficits in the development of T1DE and IO. Furthermore, the results suggest that carbohydrate counting per se does not play a key role in the depletion of SR in women with T1D, but that key factors appear to be dietary restraint and the implications on blood glucose. The drain on cognitive capacity, and reduced feelings of self-efficacy, were also found to mediate condition management. Reductions in these facets led to negative self-talk and feelings of burnout which increased the likelihood of disengagement. The findings of this programme of research should inform future research to further increase our understanding of how implementing SR interventions among individuals with T1D could inform good practise in the management of TIDE and potentially reduce incidences of T1DE and IO.