The photo-Fenton process is an appropriate method of the Advanced Oxidation Process that is used in the photocatalysis of organic dyes like crystal violet (CV). La3+ion substituted gadolinium zirconium oxide Gd(2−x)La(x)Zr2O7nanopowders (x = 0.1, 0.2, 0.3, and 0.5) have been successfully prepared by using sol–gel auto-combustion method to be used for the efficient photocatalysis of CV with photo-Fenton process. The well-crystallized defect-fluorite, structured with space group: Fm-3m, was detected using X-ray diffraction analysis. The lattice parameters were found to increase with the evaluated La3+ion concentration. The grain size of the synthesized powders increased with the increase in La3+ion content. The SAED patterns depicted fluorite structured fluorite. UV/Vis. spectrophotometer was used for the determination of band gap energy of Gd(2−x)La(x)Zr2O7nanopowders which increased with increasing La3+ion content. It was found to enhance from 4 to 3.6 eV. The visible spectrophotometer was used for determining unknown concentrations during the photocatalysis process to assure the effectiveness of the process. Overall, results illustrate that the photo-Fenton reaction on Gd(2−x)La(x)Zr2O7performed excellently in removing crystal violet (CV). The photo-remediation ratio of CV reached 90% within 1 h.