IntroductionThalassaemia is an inherited blood disorder, for which definitive treatments remain largely inaccessible. The recommended approach to reduce the disease burden is by prevention through screening. Currently, the implementation of thalassaemia preventive measures is poorly regulated in Indonesia. Thalassaemia prevention and education are best targeted to the youth, but information on their awareness towards thalassaemia is limited. This study aims to investigate the knowledge, attitude and practice (KAP) towards thalassaemia among Indonesian youth.MethodsThis observational study took place between January and May 2021. An online questionnaire was disseminated to Indonesian youth aged 15–24. Eligible respondents included carriers, unaffected individuals and individuals with unknown carrier status. The questionnaire comprised 28 questions to assess KAP. A cut-off of 75% was used to categorise participant’s KAP into poor or negative and good or positive. Descriptive statistics, χ2 test, logistic regression and Pearson correlation were performed for data analysis.ResultsA total of 906 responses were gathered, and 878 were analysed. Most respondents had poor knowledge (62.1%), positive attitude (83.3%) and poor practice (54.4%) towards thalassaemia. The results implied that respondents had limited understanding regarding the types of thalassaemia and the difference between asymptomatic carriers and individuals without the thalassaemia trait. Many (82.6%) believed they were not carrying thalassaemia trait despite the fact that most (95.7%) never got tested. Age, education, gender, residence and family income were key factors that correlated with or predicted the youth’s KAP towards thalassaemia. Older respondents and women were more likely to have good KAP.ConclusionThalassaemia screening targeted to the youth is urgently needed, and future interventions must consider sociodemographic factors that may affect how they perceive the disease. Social media appeals to the youth as an important source of information, but school, parents and health professionals should also be involved in delivering education about thalassaemia.