This study presents a novel and straightforward process for extracting vanadium from vanadium slag via an iron (III) oxide–assisted mechanochemical activation, designed to overcome the drawbacks of conventional roasting-leaching methods. The mechanochemically activated vanadium slag showed significantly higher vanadium leaching efficiency of 98.1 % under atmospheric pressure compared to the non-mechanochemically activated slag, which achieved 72.7 %. This improvement in leaching efficiency can be primarily attributed to the formation of grain refinement, lattice distortions, and increased chemical reactivity of vanadium slag. Additionally, the mechanochemical activation reduced particle size and increased the specific surface area, thereby exposing more of the vanadium-containing phase and enhancing surface free energy. Importantly, pre-oxidation of vanadium was facilitated by the generation of reactive oxygen species during mechanochemical processing, coupled with the presence of the iron (III) oxide. These changes in physiochemical properties and structure of the slag improve the interface reactivity, leading to a marked increase in vanadium leaching efficiency in alkaline solutions. Moreover, the iron (III) oxide can be replaced with vanadium tailings waste, achieving similar vanadium leaching efficiencies. This study introduces a novel method for vanadium extracting through a waste management approach using mechanochemical activation, offering a promising alternative for the environmentally responsible treatment of vanadium slag.