Adult acute myeloid leukemia (AML) is often associated with a poor prognosis, with allogeneic transplantation representing the greatest chance of cure for eligible patients. Historically, the preferred donor source is a human leukocyte antigen–matched blood relative, although only approximately 30% of patients have access to such a donor. Alternative donor sources, including matched unrelated donors, umbilical cord blood, and haploidentical related donors, are available for almost every patient and are increasingly being used for patients without a matched related donor. Survival outcomes with these alternative donor sources now approximate those of matched related donor transplants. Given the safety and success of alternative donor transplants, comparative trials are needed to reassess the optimal donor source for patients with AML. This review summarizes the available data on these alternative donor transplants. Further investigation is needed to contemporize donor selection algorithms, but, in the current era, donor availability should no longer preclude a patient's eligibility for an allogeneic blood or marrow transplant.