Theoretical and computational nanotechnology integrates the power of advanced simulations and mathematical models to understand and predict the behavior of materials at the nanoscale. By utilizing principles from physics, chemistry, and engineering, this field enables the design of novel nanomaterials and devices with specific properties, often unattainable through traditional methods. Computational models help visualize atomic structures, predict reactions, and optimize performance, reducing the need for expensive and time-consuming experimental trials. Theoretical approaches provide insight into quantum effects and molecular interactions, essential for advancing nanotechnology applications in medicine, electronics, energy storage, and environmental protection. This fusion of theory and computation is accelerating innovations that transform industries by making nanoscale innovations more efficient, sustainable, and practical.