We present near band gap optical transmission experiments in a series of GaSb–AlSb superlattices grown by molecular beam epitaxy. The spectra exhibit a steplike behavior characteristic of two‐dimensional electron systems. The absorption steps are attributed to transitions between valence and conduction states confined in the GaSb quantum wells. However, the energy of the absorption edge is smaller than that expected for a simple well, probably as a result of the effect of strain.