<p>Heavy metals are undeniably a threat to the environment. Nanocalcium-based amendments, including nano-hydroxyapatite (NHAP) and tricalcium phosphate variants, demonstrate effective immobilization of heavy metals such as Pb, Cd, Zn, Cu, and As in contaminated soils at the same time enhance soil health. We systematically reviewed articles to identify the various types of nanocalcium-based amendments and evaluate their effectiveness in immobilizing and remediating heavy metals in soil. Nanocalcium materials process remediation through various means which include sorption and precipitation, these is made possible by their nanoscale structure, high surface area, and chemical composition. Application methods include direct soil mixing, granular placement, and liquid-phase slurries. These are influenced by soil pH, texture, and organic matter content making them efficient. Nanocalcium amendments often alter soil chemistry by raising pH, increasing cation exchange capacity, and promoting the formation of stable mineral phases, which leads to the eventual reduction in metal mobility and bioavailability. Hybrid composites integrating nanocalcium, especially NHAP, with other materials like biochar improve contaminant retention and reduce metal translocation into plant tissues, achieving reductions in bioavailable metal fractions and compliance with food safety standards. Other synergistic combinations with iron oxide nanoparticles or organic amendments enhance immobilization efficiency and support microbial activity, contributing to improved plant growth and reduced oxidative stress. Ecotoxicological assessments mostly indicate low toxicity to non-target soil organisms, with microbial communities often showing recovery post-treatment. Despite the promising results, gaps remain in long-term field evaluations and molecular-level mechanistic insights, highlighting the need for extended monitoring to confirm durability, ecological safety, and sustained agronomic benefits across diverse environmental conditions.</p>