The effective use of earth-abundant electrocatalyst copper in the splitting of water as nanostructures with different combinations is central in replacing noble metals for the industrialization of hydrogen generation. Carbonaceous fuels, being front-line suppliers of energy, adversely affect the environment with greenhouse gas emission. Considering the electrocatalytic way of splitting water, it is one of the finest ways for producing pure hydrogen with a fast rate with no other undesired by-products; hence, researchers across the world have focused maximum attention to make them commercially applicable. To replace the noble metals, transition metal-based catalysts are promising. In this review, we have chosen to highlight solely the importance of Cu-based nanostructures as effective electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Moreover, various synthetic approaches with Cu nanostructures such as mono-, bi-, and tri-metallic catalysts as oxides, hydroxides, sulfides, selenides, tellurides, and phosphides were studied for OER and HER in different pH conditions. Hence, this review gives a brief understanding of Cu-based nanostructures in electrocatalytic water splitting and based on this, it can be applied with other advancements in catalysts development for viable hydrogen generation with electrocatalytic water splitting.