Abstract: Double-Double laminates, an innovative concept that offers the potential to simplify the design and manufacturing of composite laminates while further promoting structural lightweight design. Their primary advantage lies in homogenization, which enables the laminate to be treated as an anisotropic continuum, and avoids coupling effects such as extension–shear, extension–bending, and bending–twisting that must be considered in conventional designs. The analysis and design processes will be significantly simplified. However, current understanding of the homogenization mechanism and related mechanical behaviors of Double-Double laminates remains limited, and their application in engineering practice is still at an early stage with few practical cases. This study investigates the homogenization characteristics of Double-Double laminates. First, based on classical laminate theory, their homogenization advantages compared with traditional laminates are clarified. The effect of layup sequences on the homogeneity is investigated. Second, combined with the finite element model as well as experimental verification, bending performance analysis is conducted to explain size effects and layup sensitivity arising from non-homogenized laminates. Experimental results show that the bending stiffness of Double-Double laminates is significantly greater than that of the traditional laminates (Quad). Finally, two structural design and manufacturing examples of tapered laminates are presented to demonstrate the performance benefits brought by homogenization. The results from 3D scanning underscore the advantages of Double-Double laminates in terms of processability and its greater scope for optimizing process-induced deformation. The results show that Double-Double laminates not only provide theoretical simplifications in design and analysis but also exhibit promising potential for practical applications, offering valuable support for advancing this novel layup concept in engineering practice.