The destabilizing effect of the over‐reflection mechanism in stratified fluids in horizontal sheared motion is considered. It is shown that the behavior of unstable modes, induced by the contemporary presence of jumps in both the mean horizontal velocity and the Brunt–Va¨isa¨la¨ frequency located at different heights, can be interpreted in terms of successive reflections and over‐reflections at the Bru¨nt–Va¨isa¨la¨ frequency jump and at the vortex sheet, respectively. A very good accord is obtained with the predictions of the linear theory of unstable modes with small associated growth rates.