Orthotopic liver transplantation is the most effective treatment for end-stage liver disease. With better survival, the prevalence of overweight and obesity and its metabolic consequences has increased. Understanding patients' perceptions about their weight gain could contribute to its prevention and management.Using a qualitative research approach, face-to-face semi-structured interviews were conducted with 20 (12 male and 8 female) patients who had undergone liver transplantation over the previous 19 years. Thematic analysis was used to explore patients' perceptions and knowledge about their weight gain.All patients had gained more than 10% of their dry body weight since transplant; mean percentage weight gain was 29% (SD 18.5). Four themes were identified 1) reasons for weight gain, 2) knowledge about weight gain 3) barriers to weight loss and 4) prevention of weight gain. Most patients were aware of weight gain and its consequences for health. Perceived reasons for weight gain included: medication, improved health, appetite and sense of taste, continued adherence to high energy, high protein diets, psychological factors, previous alcohol or cigarette addiction and sedentary lifestyles. Barriers to weight loss were lack of motivation or energy, health problems unrelated to the transplant and lack of nutrition/dietetics health care professional support. Group programmes, dietetic and psychological follow-up as well as specialist peer-supported group education focusing on diet and physical activity after transplantation were suggested as strategies to prevent the development of overweight and obesity.This study provides qualitative evidence for patients' perspectives on weight gain following liver transplantation. These data will inform the development of a quantitative study instrument to examine weight gain and its management in a large cohort of liver transplant recipients.