Symmetry considerations reveal that an asymmetry exists relative to orthogonal 60° dislocations of thesame signin zinc‐blende structure. The effect of this asymmetry has been observed in compositionally graded crystals of In1−xGaxP and GaAs1−xPxgrown from vapor phase. It is observed that the spatial arrangement of the two sets of misfit dislocations in an orthogonal array is different. In one ⟨110⟩ direction, the misfit dislocations tend to be uniformly distributed, while in the other ⟨110⟩ direction there is a marked tendency for periodic banding of the dislocations.