Herein, we have developed a series of ternary layered double hydroxide (LDH) using pH-adjusted co-precipitation method with varying ratio of Cu, Ni and Co, which are used as an electrocatalyst for overall water splitting. (Cu3-xNix)Co2-LDHs (x = 0, 1, 2, and 3) were systematically characterized using XRD, XPS, SEM, FTIR, TEM and BET techniques. The synergistic contributions from the electrocatalytically active metals and lamellar morphology of LDHs promotes water dissociation, facilitates faster release of H2-O2 gas bubbles, ameliorate electrolyte ion diffusion and improves electron transfer rate. It is further observed that the (Cu2Ni)Co2-LDH showed excellent electrocatalytic activity for both hydrogen evolution (HER) and oxygen evolution reaction (OER) with an overpotential of 147 and 218 mV for HER and OER, respectively at 10 mA cm-2. Tafel slope was found to be lowest for (Cu2Ni)Co2-LDH. Further, the durability of the materials was also analysed by performing chronoampherometry for over 12 h. The overall water electrolytic cell using (Cu2Ni)Co2-LDH as both electrodes can reach 100 mA cm−2 at 1.65 V with outstanding durability.