Abstract: The growth of a penny-shaped crack in a functionally graded material is analyzed. The crack is perpendicular to the functionally graded interfacial zone between two fully bonded solids, and subject to inclined tension or compression loads. The functionally graded interfacial zone is treated as a nonhomogeneous solid layer with its elastic modulus varying in the thickness direction. With the superposition principle of linear elastic fracture mechanics the available stress intensity factors of the penny-shaped crack under uniformly normal and shear stresses are incorporated into the strain energy density factor criterion for prediction of crack growth. The results of the critical external loads that will cause the crack to grow at the most possible location and along the most possible direction are presented. The effects of external load direction and material parameters on the critical loads are also examined.