Abstract Functionally graded materials composed of nickel–Al 2 O 3 composites with a variety of compositions and microstructures have been fabricated at the Idaho National Engineering and Environmental Laboratories. Finite element analysis has been utilized to numerically model the residual stress distribution in a graded nickel–Al 2 O 3 joint, primarily for the purpose of optimizing the architecture of the interface to resist failure. In this paper, the applicability of using computationally efficient two-dimensional (2-D) analyses for modeling complicated three-dimensional (3-D) plate geometries are quantified for a specimen consisting of nickel and alumina plates joined by a 60 vol% Ni particulate reinforced composite interlayer to form a functionally graded joint. A 2-D generalized plane strain model is also introduced for comparison. Overall, the results indicate that the generalized plane strain model with or without rotation of the rigid bounding planes provides the most accurate description of the 3-D stress state, especially at the corner interface within the elastic region. However, the plane stress model predictions are slightly better in the ductile regions while the plane strain model predictions are better along the edge of the interface in the elastic region. Furthermore, 3-D effects are prevalent at distances within approximately 1/2 of the specimen thickness from the edge singularity in the elastic region of the specimen on the free surface and within 1/8 of the specimen thickness below the free surface. In addition, the intensity of the stresses near the corner of the 3-D model appears to increase as the specimen thickness increases, and is greater than the intensity of the stresses predicted at corresponding locations in the 2-D models.