The thin films of Zr co-doped BT (BZT) with the Zr concentrations of 0, 3%, and 5% have been deposited on the quartz substrates via the sol-gel technique with a spin coater. The microstructure and optical properties of the samples were identified by XRD and UV-Vis Spectrophotometer to investigate the properties influenced by the Zr number modification. The XRD patterns exhibited that the samples were a single-phase tetragonal structure and a shift of (101) peak was observed toward a lower angle with increasing Zr content confirming an enlargement in the lattice parameter and cell volume of the samples. On the other hand, the lattice strain and crystallite sizes reduce together with more Zr content. The optical properties examination demonstrated that the BT and BZT samples were highly transparent (~70-80%) in the visible wavelength and the absorption edges exchanged toward a lower wavelength due to the Zr doping particularly on the BZT5. The refractive index values were high categorized at ~ 4, 3.5, and 3.3 for BT, BZT3, and BZT5, respectively. Moreover, BZT possesses the lowest bandgap (3.57 eV) followed by BT (3.61) and BZT5 (3.72 eV)