The open‐circuit voltage of hybrid solar cells based on ZnO nanoparticles (nc‐ZnO) and conjugated polymer MDMO‐PPV increased significantly by replacing poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulphonate) (PEDOT:PSS) with NiOx as the anode buffer layers. The open‐circuit voltage as high as 0.828 V was obtained at high amount of ZnO (80% in weight) in the photoactive blend. Such improvement could be ascribed to the appropriate energy level of NiOx, which allows less energy loss for holes while having a sufficiently high‐conduction band minimum to function as a more efficient electron/exciton blocking layer than PEDOT:PSS. The increase of open‐circuit voltage, as well as photocurrent, resulted in a 42% improvement in power conversion efficiency. The results indicate that nickel oxide has promising potential to increase the performance of hybrid solar cells based on nc‐ZnO.