Developing gel polymer electrolyte (GPE) can solve the safety issues faced by liquid electrolyte and allow easy fabrication of dye-sensitized solar cell (DSSC). However, its power conversion efficiency (eta) still needs improvement by bettering any other parameters such as open-circuit voltage (V-OC), short-circuit current (J(SC)) and Fill Factor (FF). Herein, 4-tert-butyl-pyridine (TBP) is used as an additive with different concentrations, and its effects on the GPE-TBP are studied. The addition of TBP is beneficial in DSSC employing GPE-TBP as it can adsorb on the surface of the mesoporous TiO2 photoanode, which leads to the shifting of the quasi-fermi level of TiO2 photoanode to a higher potential. This phenomenon enhances open-circuit voltage (V-OC) of the DSSC from 615 to 750 mV upon addition of 7 wt% of TBP content to the GPE sample. However, taking into consideration all parameters in DSSC employing GPE-TBP, GPE sample containing 3 wt% of TBP shows the highest photovoltaic conversion efficiency (eta) of 8.11% under light illumination of 100 mW cm(-2).