Oesophageal cancer is a disease of increasing incidence, with those achieving an early-diagnosis requiring aggressive curative treatment, associated with an arduous post-surgical recovery and sustained impact on health related quality of life. However, as with many cancers of the digestive tract, there has been a dearth of research into the impact of the diagnosis and treatment on the patient’s psychological wellbeing. Previous research has suggested significant levels of psychological co-morbidity among the oesophageal survivor population and their family carers. Patient and carer illness beliefs have been identified as a possible determinant of poor psychological wellbeing. This thesis aims to progress our understanding of illness beliefs as a determinant of psychological distress in oesophageal cancer patients and family carers, modeling psychological theory and identifying key characteristics towards informing the development of a theoretically driven, evidence-based intervention to reduce psychological distress.