  Within D=4 N=1 supergravity theory we obtain an effective theory of the thin
wall limit for a flat domain wall configuration, interpolating between isolated
supersymmetric extrema of the matter potential. We focus on the Z_2 symmetric
flat wall and derive the supersymmetric effective action both in the bulk and
on the wall; in the thin wall limit the scalar field, forming the wall, is
frozen, and provides the delta function domain wall source, while its fermionic
partner decouples due to its large mass. In addition, the interaction between
the gravitational supermultiplet and the interaction of the matter multiplet
decouples on the wall. While the results are explicitly demonstrated within N=1
D=4 supergravity, we also provide a generalization of the result to
D-dimensions.
