The Peruvian construction sector, especially its SMEs, faces critical inefficiencies in supply chain management, particularly in procurement processes. Past research has shown that these inefficiencies lead to significant cost overruns and delays. This study addressed these challenges by implementing a procurement model integrating Lean Construction, Kaizen, and Just-In-Time (JIT). The main challenges identified were excess material purchases (20.12% of cost overruns) and late deliveries (25.84% of operations). The model reduced late deliveries from 25.84% to 8.95% and purchasing errors from 8.49% to 3.33%, confirming its effectiveness. The research has substantial academic and socio-economic implications for Peruvian SMEs, providing a solution that enhances efficiency and reduces operational costs. Further research should explore broader applications of this model and strategies to prom...