Most children, adolescents and young adults with acute lymphoblastic leukaemia (ALL) in first complete remission (CR1) have an excellent prognosis with multi-agent chemotherapy in induction, consolidation, re-induction and maintenance therapy. However, there is a subset of patients with a more guarded prognosis using this approach, who may benefit from haematopoietic allogeneic stem cell transplantation (alloHSCT). Commonly used criteria for alloHSCT in children, adolescents and young adults with ALL in CR1 include: induction failure, poor cytogenetics, persistent minimal residual disease (MRD), age, immunophenotype, white blood cell count at diagnosis and rapidity of induction response. Two-year event-free survival following alloHSCT in patients with ALL in CR1 ranges from 50 to 80% depending on disease status, donor source, conditioning therapy, age and other risk factors. Future studies should focus on more precisely identifying poor-risk features, such as disease genomics and host pharmacogenomics, refining MRD measurements, improving unrelated donor matching, reducing MRD prior to alloHSCT, and developing post-alloHSCT humoral and cellular therapy approaches.