The fracture toughness of a material is a critical factor in structural design and in the material selection process, as it ensures safe and reliable results. This Master’s thesis investigates the effect of thickness on the fracture toughness of Al2050 aluminum- copper alloy, a material widely used in aerospace and automotive industries due to its lightweight and high-strength properties. The study aims to identify the optimal thickness that maximizes fracture resistance while maintaining mechanical performance. Double Edge Notched Tensile (DENT) specimens of varying thicknesses were tested under controlled conditions to evaluate fracture toughness using the Essential Work of Fracture (EWF) methodology.