The transverse failure response of unidirectional fiber-epoxy systems is studied by means of finite element simulations. An interface damage model is used for modeling fiber debonding and epoxy cracking. The convergence of the numerical results upon mesh refinement is analyzed. It is found that the failure response depends on the relative strength and relative toughness of the fiber-epoxy interface and the epoxy matrix. The tensile failure response of epoxy systems containing multiple fibers is also analyzed. In addition, the simulations demonstrate the influence on the failure response by the relative strength of the fiber-epoxy interface and the epoxy matrix, and by the fiber volume fraction and fiber distribution. The simulated fracture ...