Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment option for patients with acute lymphoblastic leukemia (ALL) very high-risk in first complete remission and relapsed disease that achieve remission patients. There is considerable variability in the regimens preparatory for conditioning patients to be transplanted. In this systematic review, we identify the impact of reduced-intensity regimen (RIC) or non-myeloablative (NMAC) on HSCT in pediatric ALL patients in terms of overall survival (OS) and disease-free survival (DFS) as reported in the scientific literature. Information was searched on nine databases, gray literature and bibliography cited in the selected articles, describing the results of HSCT in ALL in children between January 01, 2007, and June 30, 2021, with different preparative regimens. The literature search yielded an overall of 3841 articles; two articles were duplicates and rejected. This first selection included 363 articles, and 95 were selected for a complete reading. Finally, 16 articles that met the inclusion and exclusion criteria were included, which analyzed 2136 patients with ALL. RIC, NMAC, or reduced-intensity myeloablative regimen (RTMAC) was administered to 520 patients, demonstrating OS and DFS like other cohorts undergoing MAC. This article concludes the use of RIC, NMAC, or RTMAC is a reasonable option for those patients with ALL who require a transplant and who suffer from other comorbidities or have previous transplants, offering survival rates comparable with myeloablative regimens that, in combination with new alternatives such as immunotherapy, may become the best alternative.