We report the synthesis of a novel nanohybrid based on nickel sulfide (NiS) nanoparticles decorated reduced graphene oxide (rGO) following a facile hydrothermal approach for application as Pt-free counter electrode (CE) in dye sensitized solar cells (DSSC). The DSSC devices fabricated using this NiS/rGO nanohybrid film as CE showed an impressive power conversion efficiency (PCE) of 9.5% and a fill factor of about 0.78 when illuminated by AM 1.5 G simulated solar light. These values are well above those reported previously for DSSCs fabricated with Pt free CE and thus establishes the potential of the NiS/rGO nanohybrid as an excellent low-cost CE material for DSSC fabrication. The improvement in the PCE is due to improved electro-catalytic activity of the NiS/rGO nanohybrid for reduction of the triiodide caused by the synergistic effects of highly catalytic NiS nanoparticles and electrically conductive rGO. Display omitted •NiS/rGO nanoybrids were synthesized using a facile and cost-effective hydrothermal approach.•Uniformly distributed NiS nanoparticles with average size of 25 nm were observed on rGO sheets.•DSSCs fabricated with NiS/rGO nanoybrid counter electrode showed efficiency as high as 9.5% suggesting its potential replace Pt.•Small charge transfer resistance of the nanoybrid electrode is responsible for the high efficiency of the DSSC.