The use of metal oxide nanoparticles for the development of cost-effective glucose biosensors has been receiving increased attention. Enzymatic and non-enzymatic glucose sensor using polyethylene glycol (PEG) grafted manganese ferrite (PEG-MnFe2O4) nanoparticles (NPs) modified onto a glassy carbon electrode (GCE) is reported in the present study. XRD and Raman studies confirmed the cubic spinel structure of MnFe2O4. The immobilization of glucose oxidase (GOx) on PEG-MnFe2O4 (GOx@PEG-MnFe2O4) was validated using FTIR and TGA. Sensing electrodes exhibited well-defined redox peaks in 0.1 M phosphate buffered saline (PBS) solution at pH 7.4 against the reference electrode Ag/AgCl. GOx@PEG-MnFe2O4/GCE displayed a sensitivity of 1.985 μA mM-1 cm-2 in the linear range of 1 to 20 mM with a limit of detection (LOD) of 0.132 mM whereas non-enzymatic sensor exhibited a sensitivity of 1.044 μA mM-1 cm-2 in the linear range of 1 to 10 mM with a LOD of 0.099 mM. The lower Michaelis constant value indicates greater affinity towards glucose for the enzymatic sensor. GOx@PEG-MnFe2O4 revealed selectivity specifically for glucose over various interferants such as fructose, lactic acid, sucrose, uric acid and ascorbic acid. In addition, this enzymatic sensor demonstrated better reproducibility and lifetime. © 2020 The Author(s). Published by IOP Publishing Ltd.