This volume consists of 11 chapters focusing on the application of lightweight materials in structural engineering applications. The contents of this volume cover various types of lightweight structures namely thin-walled tubular structures, composites, shape memory alloy, iron-based scaffold, tin-slag polymer and honeycomb structures. Lightweight materials have been used prevalently in structural applications particularly in vehicular design. In advanced component designs, a lightweight feature is of primary interest for achieveing a combination of high stiffness and strength with significant weight savings. This book treats the application of lightweight materials in enhancing the structural behaviours under various loading conditions that contribute to safety. Most chapters emphasize on the mechanical behaviour of the structures by applying lightweight material in the design. Several chapters also outline the contributions of typical composite materials in improving mechanical performances. The final chapter presents the application of lightweight materials in designing vehicular structures aimed for less fuel consumption. Materials presented in this book could provide research information, guidelines or references for postgraduate students, researchers and professionals in the industries.