This study investigates the synthesis, characterization, and photocatalytic performance of iron lanthanum oxide nanoparticles (FeLO NPs) tailored for environmental remediation applications. The nanoparticles were synthesized using a co-precipitation method involving ferrous and lanthanum nitrates, followed by pH adjustment and calcination. Characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) were employed to analyze the structural and morphological properties of the nanoparticles. XRD confirmed the crystalline nature of FeLO NPs with peaks corresponding to standard indices, while SEM images revealed a heterogeneous surface topology conducive to catalytic activity. FTIR analysis detected functional groups and bonding interactions indicative of the complex molecular composition of the nanoparticles. The Brunauer-Emmett-Teller (BET) method determined a surface area of 2.43 m²/g. Photocatalytic testing using methylene blue (MB) under UV and visible light showed that FeLO NPs achieved up to 90% degradation of the dye, highlighting their effectiveness in pollutant breakdown. The degradation mechanism involved the formation of electron-hole pairs, facilitating radical generation and subsequent pollutant decomposition. This study underscores the potential of FeLO NPs as efficient and sustainable photocatalysts for the treatment of dye-polluted wastewater.