Strain-hardening, cement-based composites (SHCC) are a novel class of fiber-reinforced concretes which exhibit high tensile strain capacity and crack control prior to failure localization, making them suitable for application as strengthening layers or as main materials for construction elements exposed to severe loading and environmental conditions. As opposed to their tensile properties, the shear performance of SHCC has been only scarcely investigated. In the context of structural strengthening against dynamic actions such as impact loading, the paper at hand describes the development, implementation, and testing of a shear testing setup for ductile cementitious composites. The development of the testing setup had as its target its integration in a gravity-driven Split-Hopkinson tension bar (SHTB) and required both finite element modeling and experimental testing. The numerical modeling aimed at a detailed parameter study of the device geometry, boundary conditions, and notch configuration of the material specimens as well. The experimental program implied both quasi-static and impact shear experiments on normal-strength SHCC made with ultrahigh-modulus polyethylene (UHMWPE) fibers. Both the numerical and experimental analyses demonstrated the inapplicability of one-dimensional wave analysis in deriving specimen shear response. This was solved by applying high-speed optical measurements with subsequent digital image correlation (DIC), which also allowed the accurate evaluation of the fracture modes related to load history. The study highlighted the pronounced influence of loading and boundary conditions on the specimens’ response and demonstrated the necessity of complementary numerical analyses to derive the constitutive relationships of SHCC. Furthermore, it serves as basis for further device optimization in respect of structural and inertial effects.