The structural analysis of a SiC/SiC composite first wall in a tokamak fusion reactor is explored using the finite element method. The analysis is done in three dimensions under thermal and pressure loads. The effect of the three-dimensional analysis on the results is compared with that for the two-dimensional analysis. The comparison indicates that for laminated SiC/SiC composite structures, the two-dimensional analysis, which ignores the effect of the stacking sequence of the laminate and the effect of the interlaminar shear stress, is insufficient for reactor design.