Design of inexpensive and highly efficient bifunctional electrocatalyst is paramount for overall water splitting. In this study, amorphous Ni-Fe-P alloy was successfully synthesized by one-step direct-current electrodeposition method. The performance of Ni-Fe-P alloy as a bifunctional electrocatalyst toward both hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) was evaluated in 30 wt% KOH solution. It was found that Ni-Fe-P alloy exhibits excellent HER and OER performances, which delivers a current density of 10 mA cm(-2) at overpotential of similar to 335 mV for HER and similar to 309 mV for OER with Tafel slopes of 63.7 and 79.4 mV dec(-1), respectively. Moreover, the electrolyzer only needs a cell voltage of similar to 1.62 V to achieve 10 mA cm(-2) for overall water splitting. The excellent electrocatalytic performance of Ni-Fe-P alloy is attributed to its electrochemically active constituents, amorphous structure, and the conductive Cu Foil. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.