Electroabsorption of strained‐layer InxGa1−xAs/GaAs superlattice structures grown by molecular beam epitaxy on GaAs substrates was experimentally investigated. Its spectral characteristics were found to be similar to those of Franz–Keldysh electroabsorption of bulk semiconductor materials, and suggest that the widths of ground‐state electron and hole minibands might be larger than the maximum tilt of the potential well caused by an applied voltage. We attribute the electroabsorption of such superlattices to photon‐assisted tunneling between ground‐state electron and heavy hole minibands.