The construction sector in Peru significantly contributes to economic development, with SMEs playing a vital role. However, these enterprises often face inefficient inventory management, leading to increased costs and material waste. This study proposes a Lean-based inventory management model tailored for construction SMEs to address these challenges. The model integrates tools such as the 5S methodology, demand forecasting, and optimized inventory policies to streamline processes and enhance efficiency. Implementation results demonstrated a 10% reduction in average inventory levels and a 40% decrease in defective product rates, indicating substantial operational improvements and cost savings. This research contributes to existing literature by providing a practical framework for inventory optimization in construction SMEs and underscores the socioeconomic benefits of adopting Lean practices. The study advocates for broader application and further exploration of Lean methodologies within the construction industry to promote sustainable operational excellence.