Thalassaemia is a life-long illness that exists globally. The quality of life of adolescents with thalassaemia could differ based on the health policies of a specific region, existing levelof socio-economic development and the illness related variables. This study examines the relationship between socio-demographic and disease-related variables with the quality of life among adolescents with thalassaemia involving multiple treatment centers spread throughout various locations in Malaysia. Participants included 218 adolescents (male=108; female 112) with mean age of 13.86 (SD=2.40). They completed the questionnaire consisting of demographic information, illness-related variables, and Pediatric Quality of Life Inventory 4.0 (PedsQL). The participants in this study was found to have higher total summary score (Mean = 69.64, SD = 14.03), psychosocial health (Mean = 70.23, SD = 14.91), emotional (Mean = 72.12, SD = 20.66), social (Mean = 79.82, SD = 17.37), and school (Mean = 58.69, SD = 16.77) functioning but with lower physical health (Mean = 68.50, SD = 17.22) as compared to previous study that was done in Kuala Lumpur. Findings also shows a significant positive correlation between level of education and frequency of hospitalization (r = .156, p < 0.05), frequency of transfusion (r = .152, p < 0.05), and physical health (r = .186, p < 0.01). An increase in the frequency of transfusion was found to significantly increase social functioning (r = .137, p < 0.05). Other significant correlations are discussed in addition to the quality of life experienced by patients with thalassaemia in different region of theworld.