<p>Al-Ni-Co alloys have been considered as promising engineering materials due to their functional properties and wide application prospects. However, the widespread application of their glassy counterparts, Al-Ni-Co Metallic Glasses (MGs), is limited by their poorly understood property of glass-forming ability (GFA). Herein, we report the structural evolution in the glassy state as a potential tool to optimize the GFA in the Al-Ni-Co ternary diagram, using molecular dynamics (MD) simulations. To this aim, a total of 66 compositions in Al-Ni-Co ternary diagram, which includes monatomic, binary and ternary systems were generated and characterized their atomic structure. The study found that Al and Ni-based alloys are the best glass-formers compared to the Co-based alloys, indicating a strong correlation between the atomic structure and the GFA. Importantly, the highest glass former correlates also with higher dispersity of structural units at the short range order (SRO) and the evolution of their interconnectivity at the medium range order (MRO). Overall, this work both improves our fundamental understanding of optimizing the GFA from microstructural perspectives and provides an interesting a priori opportunity for future research to extend beyond the here-used analysis and identify the regions around the highest GFA within the Al-Ni-Co ternary diagram.</p>