This chapter discusses the role of Building Management Systems (BMS) in improving energy efficiency and sustainability in the building sector. The chapter discusses how BMS integrates HVAC, lighting, and renewable energy systems to optimize energy use, enhance sustainability, and mitigate environmental impact. It explores the implementation of advanced algorithms to further optimize building performances and operational efficiency. Critical challenges, including dynamic modeling, energy balance management, and reinforcement learning are also discussed. Overall, the chapter highlights the significance of BMS in supporting energy-efficient building operations and facilitating the transition to a smarter and more sustainable environment.