An elastic analysis of dislocations in isotropic media has been applied to study the interaction of dislocations on intersecting {111} planes at a coherent twin boundary in the face‐centered‐cubic lattice. The nature of energetically favorable barriers formed by such reactions is determined and their equilibrium separations are given, in addition to the equilibrium separations for the barriers found on intersecting {111} planes in the face‐centered‐cubic structure. The importance of such configurations, and especially the effect of the twin boundary, on work‐hardening behavior is discussed.