This chapter explores the economic dimension of sustainable construction, positioning it as a critical pillar alongside environmental and social sustainability. It introduces construction economics as a foundational concept, highlighting its evolution from a cost-control function to a holistic approach addressing the full life-cycle cost of projects. The chapter emphasises the need to assess construction decisions not only by initial capital outlay but also by long-term social and environmental costs and benefits. Through discussions on life cycle costing and cost-benefit analysis, the chapter equips readers with essential tools for evaluating the economic sustainability of construction projects. It also examines financial mechanisms such as tax incentives, grants, low-interest loans, and green certifications that support eco-friendly practices. A key theme is the trade-off between cost efficiency and sustainability, posing questions such as: at what environmental or social cost is a reduction in construction expenditure justified? The chapter ultimately advocates for economically rational and ethically responsible decision-making that aligns with sustainable goals. By integrating client value systems with environmental ethics and social impact, construction economics becomes a powerful tool for achieving resilient, high-quality, and cost-effective built environments. This chapter offers both theoretical insights and practical frameworks to guide construction stakeholders in navigating the complexities of sustainable project delivery.