"Experimental Testing, Manufacturing and Numerical Modelling of Composite and Sandwich Structures" is an essential resource for researchers, engineers, and industry professionals in materials science and engineering. This comprehensive volume covers the latest advancements in the characterization, manufacturing, behaviour prediction, and sustainability of composite and sandwich structures. The special issue begins with an editorial overview, followed by detailed papers on the effects of high-current pulsed electron beams, graphene aerogels, fatigue life prediction in carbon fibre-reinforced polyamide-6, and fracture behaviour under biaxial tensile loads. It details innovative manufacturing techniques, such as machining processes and coating methods, and presents sophisticated models to predict the composite behaviour under various stresses. The special issue also explores the optimization of adhesive joints, non-destructive inspection techniques for sandwich structures, and the performance of materials in high-speed trains and piezoelectric actuators. Additionally, it addresses the need for sustainability with biocomposite materials derived from Andropogon halepensis and biodegradable composites using caffeine-treated wood. This volume aims to bridge the gap between theoretical research and practical application, offering detailed experimental and numerical insights to advance the knowledge and application of composite and sandwich structures.