Acquired bone marrow failure disorders (BMFs) often present diagnostic complexity due to overlapping clinical and morphological features. This chapter addresses entities that intersect with aplastic anemia (AA), including hypoplastic myelodysplastic syndrome (hMDS), idiopathic cytopenias of undetermined significance (ICUS), clonal hematopoiesis of indeterminate potential (CHIP), paroxysmal nocturnal hemoglobinuria (PNH), T-cell large granular lymphocyte (T-LGL) leukemia, and undiagnosed congenital marrow failures. Distinguishing among these disorders requires integration of clinical features, marrow histopathology, cytogenetics, molecular data, and immunologic markers. Somatic mutations and clonal hematopoiesis complicate the diagnostic landscape but also provide insight into disease evolution and therapeutic options. Single lineage cytopenias such as pure red cell aplasia or immune thrombocytopenia may precede AA. Some overlapping entities, including hMDS and T-LGL, may respond to immunosuppressive therapy, reinforcing shared pathogenic mechanisms. Early and accurate recognition is vital, particularly to avoid inappropriate treatment in congenital cases. This chapter emphasizes the importance of diagnostic vigilance in managing overlapping BMF syndromes.