In this report, silver nanoparticles (Ag NPs) were successfully deposited on graphene oxide (GO) sheets to form GO-Ag nanocomposite using garlic extract and sunlight and the nanocomposite modified glassy carbon (GC) electrode was applied as an electrochemical sensor for the detection of nitrite ions. The formation of GO-Ag nanocomposite was confirmed by using UV-visible absorption spectroscopy, TEM, XRD and FTIR spectroscopy analyses. Further, TEM pictures showed a uniform distribution Ag on GO sheets with an average size of 19 nm. The nanocomposite modified electrode produced synergistic catalytic current in nitrite oxidation with a negative shift in overpotential. The limit of detection (LOD) values were found as 2.1 µM and 37 nM, respectively using linear sweep voltammetry (LSV) and amperometric i-t curve techniques. The proposed sensor was stable, reproducible, sensitive and selective toward the detection nitrite and could be applied for the detection of nitrite in real water sample.