GaFeO3 is a multiferroic material with magnetoelectric properties which commonly fabricated via conventional solid-state and sol-gel methods using hazardous chemicals and energy consuming conditions. This study reports a novel green synthesis of GaFeO3 nanoparticles using Mitragyna speciosa leaf extract to overcome such challenges. Material characterizations elucidate the structural, optical, and morphological properties of prepared GaFeO3. XRD and FTIR analyses confirmed the orthorhombic structure and Ga–O/Fe–O vibrational modes of GaFeO3 nanoparticles. Furthermore, UV-Vis DRS result showed that GaFeO3 is optically active under visible light exposure (2.27 eV), suggesting its potential as remarkable photocatalyst with excellent light harvesting ability. FESEM and HRTEM images revealed high-purity nano-scaled spherical particles of GaFeO3 (∼142 nm) with noticeable (130) plane lattice fringes, demonstrating superior crystallinity. XPS and PL studies uncovered intrinsic defect states such oxygen vacancies present in GaFeO3 crystal, which serves as electrons trap and suppress recombination. It is successfully demonstrated that our facile method yields GaFeO3 nanoparticles with promising applications in photocatalysis or optoelectronics, establishing new insights into nanotechnology development. © 2026 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license. http://creativecommons.org/licenses/by-nc-nd/4.0/