This study investigates the use of graphene oxide (GO) into limestone calcined clay cement (LC3) to enhance the immobilization of heavy metal ions from ferronickel slag. Various macro- and micro-characterization techniques, including compressive strength, toxicity characteristic leaching procedure, heat of hydration, X-ray diffraction (XRD), thermogravimetric analysis/derivative thermogravimetry (TGA/DTG), and scanning electron microscopy (SEM), were employed to evaluate the effectiveness of GO on the solidification/stabilization technique. The results reveal that incorporating GO increased the compressive strength of LC3 mortars at both 7 d and 28 d. Additionally, the use of GO improved the immobilization of heavy metal ions, reducing leaching concentrations of Cr and Mn by 20% and 30% at 28 d, respectively. Isothermal calorimetry, TGA/DTG, XRD, and SEM analyses further elucidated the accelerated hydration, mineral crystal phase changes, denser microstructure, and improved interfacial transition zone of GO-modified LC3 mixtures. The study provides the potential of integrating nanotechnology into LC3 cement for environmentally sustainable waste management strategies.