Low-cost and environment-friendly dye-sensitized solar cells were fabricated using titanium dioxide nanoparticles sensitized by a new natural dye extracted from Terminalia chebula dry fruits. Pure titanium dioxide (TiO2) nanoparticles in anatase phase were synthesized by sol–gel process and pre-dye-treated TiO2 nanoparticles were synthesized by mixing the natural dye during synthesis itself using our modified sol–gel process. This pre-dye treatment with natural dye has yielded colored TiO2 nanoparticles with uniform adsorption of natural dye, reduced agglomeration, less dye aggregation and improved morphology. The pure and pre-dye-treated TiO2 nanoparticles were subjected to structural, optical, spectral and morphological studies. Dye-sensitized solar cells fabricated using the pure and pre-dye-treated TiO2 nanoparticles sensitized by T. chebula natural dye showed promising solar light to electron conversion efficiencies of 0.86% and 1.49%, respectively. The pre-dye-treated TiO2-based DSSC showed 73% improvement in efficiency when compared to conventional DSSC.