BACKGROUND: Osteosarcomas (OS) are malignant bone tumors prevalent in adolescents, characterized by aggressiveness and early metastasis. Current treatments including surgery and chemotherapy face challenges due to drug limitations and the complex tumor microenvironment (TME). METHODS: Tumour membranes (TM) derived from OS cells and macrophage membranes (MM) derived from macrophages were mixed to create hybrid membranes (HM), which were subsequently used to encapsulate microRNA-665(miR-665)-loaded Poly lactic-co-glycolic acid (PLGA) nanoparticles, forming HM@PLGA/miR-665 complexes. In vitro characterization included physical properties, colocalization studies, and assessment of macrophage polarization. In vivo experiments involved a nude mouse model to evaluate tumor targeting, biosafety, and therapeutic efficacy. RESULTS: The HM@PLGA/miR-665 complexes exhibited good physical characteristics and stability. In vitro, the complexes significantly altered the M1/M2 macrophage ratio, promoting M1 polarization and inhibiting M2 polarization. Macrophage supernatants from HM@PLGA/miR-665-treated cells inhibited proliferation, migration, and induced apoptosis in MG-63 osteosarcoma cells. In vivo, the complexes effectively targeted tumor tissues, showed good biosafety, and significantly inhibited OS progression, promoting tumor cell apoptosis and altering the M1/M2 macrophage ratio. CONCLUSION: The HM@PLGA/miR-665 delivery system successfully targeted OS by modulating macrophages in the TME, exhibiting potential as a novel therapeutic strategy for OS.