Haploidentical transplantation is a type of stem cell transplant in which the donor is a haploidentical (half-matched) family member, usually a parent, sibling, or child. This type of transplant is used when a fully matched donor is not available. Haploidentical transplantation has become an important option for patients who need a stem cell transplant but do not have a fully matched donor. In haploidentical transplantation, the donor's immune system is only partially matched to the recipient, so there is a higher risk of graft rejection or graft-versus-host disease (GVHD). However, advances in haploidentical transplantation techniques, such as using T-cell depletion or post-transplant cyclophosphamide, have helped reduce these risks and improve outcomes. Research in haploidentical transplantation focuses on optimizing donor selection, conditioning regimens, and post-transplant care to improve transplant outcomes and reduce complications. Studies also explore novel approaches, such as using novel agents to prevent GVHD or enhance engraftment, to further improve the success of haploidentical transplantation.