ABO3-resembled perovskite oxides have been extensively used for heterogeneous catalysis and energy storage applications. In current work, lanthanum-ferrite (LaFeO3) perovskite oxide (PO) has been prepared using Terminalia arjuna (TA) leaf extract followed by evaluation of its degradation efficacy against malachite green (MG) under UV-light. Synthesized PO was analyzed using different state of the art analytical techniques. FTIR peaks appearing at 3608, 645, and 552 cm−1 evident the formation of PO while in UV–Visible spectrum absorption band at 420 nm confirmed the same. The crystallinity of the synthesized PO was determined through XRD which confirmed hexagonal structure having crystallite size about 25.78 nm and FESEM exhibited seaweed-like morphology of PO. The results of dye degradation studies have shown excellent percentage degradation (88.7 %) of MG in the presence of PO and the reaction followed zero-order kinetics. Effect of different factors on degradation of MG dye was also recorded and possible mechanism of dye degradation has also been presented. On the basis of current study, authors have concluded that lanthanum-ferrite LaFeO3 perovskite oxide can be synthesized employing green method with efficient dye degradation potential. The results will be helpful in designing and synthesizing ABO3-resembled perovskite oxides using green method based on plant extract.