Abstract Directionally dependent cracking along the interface of a Cu/Al2O3 bicrystal has been analyzed using continuum mechanics. This work extends previous analyses by considering the elastic anisotropy and plastic deformation of copper. The goals of the analysis are: (1) To provide a possible continuum explanation of the experimentally observed directionally dependent cracking, and (2) to understand the effect of continuum deformation on the competition between dislocation nucleation at a crack tip (i.e., tip blunting and alleviation of the stress concentration) and cleavage. First, the mode mixity of the elastic fields at the crack tip is calculated by considering the traction vector on the interface as derived from anisotropic elasticity. This is compared to the results from isotropic elasticity. The effects of anisotropy, as pertaining to dislocation nucleation and cleavage, are discussed. Elastic-plastic FEM analyses within both the `small strain' and finite deformation formulations have been performed for the two crack directions in. Furthermore, a variety of hardening laws, including ideal plasticity, were used to investigate the robustness of the solutions. Comparisons between the FEM analyses show that the general sectorial nature of the crack tip stress fields isthe same for all hardening laws chosen. The effects of geometrical hardening and softening are pronounced in a finite deformation, ideal plasticity analysis. However, even moderate hardening greatly diminishes these effects. If the hardening law saturates, the resulting near tip fields are similar to those of an ideally plastic material. The two crack tip orientations affect the nature of the localization of the plastic deformation. These effects are discussed in the context of different hardening laws. In addition, the interface traction phase angle is changed significantly by the plastic deformation with consequences regarding dislocation nucleation and cleavage. Overall, no clear continuum-based explanation of directionally dependent fracture was found, but it is clear that elastic anisotropy and plastic deformation should, in general, be taken into account. Finally, critical problems encountered in this type of analysis are identified and some directions for future research are suggested.