Depositing light scattering film on top of the photoactive layer of dye-sensitized solar cells (DSSCs) is one method to boost the device efficiency. Therefore, mesoporous MCM-41 and CeO2 were prepared and coated on TiO2 photoactive layer in both their pure and composite (1–4 wt% CeO2:MCM-41) forms by doctor blade technique. XRD, FESEM, EDS, TEM, BET, FTIR, DRS, and PL analyses were employed to characterize all compounds. Additionally, the power conversion efficiency (PCE), dye adsorption capacity, and charge transfer parameters of various DSSCs were measured. The data taken from J-V plots indicated that the highest conversion efficiency belonged to 2 wt% CeO2:MCM-41 when was used as the scattering layer which could boost the efficiency up to 7.42% with fill factor (FF), open-circuit voltage (Voc) and short-circuit current density (Jsc), respectively, equal to 0.48, 0.752 V, 20.55 mA.cm−2, confirming 78.8% greater efficiency than the bare TiO2 containing DSSC (PCE = 4.15%, FF = 0.39, Voc = 0.736 V, Jsc = 14.45 mA.cm−2). In fact, once 2 wt% CeO2:MCM-41 with large particles was applied, according to Mie's theory, prolonged the light path through incident light scattering, which resulted in more light harvesting by photoanode material, further dye molecules excitation, and improvement in the current density. Also, because of the insulating nature of silica material in 2 wt% CeO2:MCM-41 layer, it reduced the charge recombination process and accelerated the transfer of electrons from the TiO2 photoanode to the Pt counter electrode via the external circuit. Besides, high porosity and huge surface area (757.34 m2/g) of 2 wt% CeO2:MCM-41 promoted dye molecules to be adsorbed additionally which generated extra photoelectrons.