Addressing soil pollution due to heavy metals is becoming increasingly urgent worldwide, as these elements, including highly toxic lead, pose significant health risks, including cancer. Heavy metals, which are detrimental to organisms and incapable of natural breakdown into less harmful forms, necessitate active removal methods such as stabilization/solidification, soil washing, or electrokinetic remediation. This research applied the stabilization/solidification approach to treat lead-polluted soil, examining the effects of varying lead levels on the treated soil. The study assessed the compressive strength and leaching behavior of soils employing biochar derived from moringa seed waste at a 5% dose. It was observed that soil with an initial lead concentration of 10,000 mg/kg showed slightly higher lead leaching compared to those with 5000 mg/kg concentration after 28 days of curing, and lower contamination levels exhibited higher soil pH values, too. Furthermore, the compressive strength of the treated soil decreased as lead concentration increased from 5000 to 10,000 mg/kg. Thus, it is deduced that higher lead concentrations hinder the stabilization process, reducing its effectiveness as soil lead content increases.