Acute myeloid leukemia is a highly invasive and heterogeneous malignant tumor. Plantamajoside, a natural compound extracted from Plantago asiatica L., has been shown to exhibit the inhibitory effect on a variety of tumors. Herein, we have evaluated the nature of the effect of plantamajoside on MOLM-13 and HL-60 cells—two acute myeloid leukemia cells—by measuring parameters such as cell viability, proliferation, apoptosis rate, cell cycle arrest, and relative expression of BCL2-associated X protein, B-cell lymphoma 2 protein, cleaved-caspase-3, protein kinase B, and p65 proteins. These measurements led us to conclude that plantamajoside suppresses the proliferation of both MOLM-13 and HL-60 cells via inhibiting nuclear factor-kappa B and phosphatidylinositol 3-kinase/protein kinase axis in a dose-dependent fashion.