This contribution addresses moderately large deflections of a slightly precurved simply supported beam composed of three layers symmetrically disposed about the central axis. The elastic beam layers are flexibly bonded and thus exposed to interlayer slip. Since the displacements of the supports are fully restrained, the static response is geometrically nonlinear. The results of an application example demonstrates the grave effect of interlayer slip on the nonlinear deflection of slightly precurved layered beams.