In this study, we report enzyme-free glucose sensors based on palladium (Pd) nanoparticles deposited onto Co3O4 nanostructures. A simple, low-temperature aqueous method was used for the fabrication of Co3O4 nanostructures. Then, Pd nanoparticles were decorated onto Co3O4 nanostructures using the ultraviolet reduction method. Morphology, elemental composition and crystalline features of the proposed composite nanostructures were investigated by powder X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy techniques. Cyclic voltammetry and linear sweep voltammetry were used to investigate the electrochemical behaviour of Pd-Co3O4 nanostructures during glucose sensing. The proposed nanostructures showed excellent electrochemical activity for the quantitative detection of glucose at a potential of 0.6 V vs. Ag/AgCl. Importantly, the fabricated enzyme-free glucose sensor shows a linear response over the range of 1-6.0 mM glucose, with a limit of detection of 0.01 mM. The interference study was also carried out to probe the selectivity of Pd-Co3O4 nanostructures towards glucose detection in the presence of different interfering substances. The combined results attest that the as-synthesized Pd-Co3O4 nanostructures are highly stable and selective for the detection of glucose, suggesting their great potential for the quantitative determination of glucose in different biological fluids.