In this study, a novel nanocomposite of graphene oxide/zinc based metal-organic framework (GO/MOF) was prepared through a simple solvothermal method. The electrochemical As(III) sensing capability of the nanocomposite was explored by casting the GO/MOF on a glassy carbon electrode (GCE), followed by an electrochemically reduction of GO. As(III) detection was performed by the differential pulse anodic stripping voltammetry (DPASV) method after closed-circuit mode. The present sensor showed excellent electrochemical performance such as a wide linear range from 0.2 to 25 ppb (μg/L), low detection limit (S/N = 3) of 0.06 ppb and good reproducibility with a relative standard deviation (RSD) value of 2.1%. The detection limit of As(III) is lower than the threshold value set by the Environmental Protection Agency (EPA) in drinking water. A good selectivity for As(III) detection by the proposed Gr/MOF-GCE was also demonstrated. Finally, this platform was employed for the As(III) monitoring in environmental water samples, and the accuracy of obtained results were confirmed by inductively coupled plasma-optical emission spectrometer (ICP-OES) system.