Sustainable engineering is the practice of designing systems, products, and infrastructure that meet current needs without compromising future generations. It integrates environmental, social, and economic considerations into every stage of engineering, from planning and design to operation and disposal. Core principles include life cycle thinking, resource efficiency, pollution prevention, and ethical responsibility. Sustainable engineers adopt a systems approach, seeking solutions that minimize ecological impact, use renewable materials, and promote social equity. Applications span green buildings, renewable energy, water conservation, sustainable transport, and climate-resilient infrastructure. With tools like Life Cycle Assessment (LCA) and innovations in clean technology, engineers play a vital role in combating climate change and resource depletion. Challenges such as lack of awareness, economic barriers, and institutional resistance require education, policy support, and cultural shifts. Especially in rapidly developing regions, sustainable engineering is crucial for achieving inclusive and long-term development.