Alpha-mangostin (AM), a significant component isolated from the pericarp of mangosteen (Garcinia mangostana L.), has been demonstrated as a potential compound for the treatment of cholangiocarcinoma (CCA). Due to its hydrophobic nature, however, its clinical uses may be limited by its low aqueous solubility, poor stability, and low bioavailability. The present study aimed to formulate and characterize the AM-loaded PLGA nanoparticles (AM-PLGA-NPs) and further evaluate the antiproliferative and proapoptotic activities, including the inhibitory activities on CCA cell (CL-6 and HuCCT-1) invasion and migration. The AM-PLGA-NPs were prepared using PLGA MW 7000â17,000 and 38,000â54,000 by the solvent displacement method. The methods used to evaluate these activities included a MTT assay, flow-cytometry, QCM ECMatrix cell migration, and cell invasion assays, respectively. The optimized AM-PLGA-NPs were characterized for physical (particle size and morphology, polydispersity index, and zeta potential) and pharmaceutical (encapsulation efficiency, loading efficiency, and drug release profile) parameters. AM-PLGA-NPs showed relatively potent and selective antiproliferative and proapoptotic activities in both CCA cell lines in a concentration- and time-dependent manner. The results revealed that the PLGA nanoparticles could be a suitable nanocarrier to encapsulate AM for its delivery to the CCA cells.