This study investigates the biocompatibility and physicochemical properties of sodium alginate-based nanocomposites reinforced with TiO₂, ZrO₂, and MgO nanoparticles for tissue engineering applications. The nanocomposite films were prepared via a solution casting method and characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), contact angle measurements, swelling analysis, and MTT assay. XRD results confirmed the coexistence of the amorphous alginate matrix with crystalline nanoparticle phases. FTIR analysis revealed strong interactions between alginate functional groups and nanoparticles. SEM observations showed a transition from a smooth morphology to a rough and heterogeneous structure upon nanoparticle incorporation. Contact angle and swelling studies demonstrated enhanced hydrophilicity and water absorption capacity. The MTT assay confirmed high cell viability, indicating excellent biocompatibility. Overall, the incorporation of metal oxide nanoparticles significantly improved the structural, surface, and biological properties of sodium alginate, making these nanocomposites promising candidates for tissue engineering applications.