Abattoir wastewater is a significant source of heavy metal pollution, necessitating effective remediation strategies. This study investigated the adsorptive removal of selected heavy metals lead (Pb²⁺), copper (Cu²⁺), and chromium (Cr³⁺) from abattoir wastewater using synthesized cadmium sulfide (CdS) nanoparticles. The nanoparticles were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer Emmett Teller (BET) analysis, confirming a cubic crystal structure, nanoscale morphology, and high specific surface area of 86.4 m²/g. Batch adsorption experiments were conducted at varying pH (3–8), contact time (10–120 min), adsorbent dosage (0.5–3.0 g/L), and initial metal concentrations (10–100 mg/L). Maximum removal efficiencies of 94.3%, 91.7%, and 89.5% were achieved for Pb²⁺, Cu²⁺, and Cr³⁺, respectively, at pH 6.0. Equilibrium data conformed best to the Langmuir isotherm model (R² > 0.99), indicating monolayer adsorption, while kinetic data fitted the pseudo-second-order model, confirming chemisorption as the dominant mechanism. These findings establish CdS nanoparticles as a highly efficient adsorbent for heavy metal remediation from abattoir wastewater.