Self‐consistent calculations performed on small superlattices provide evidence for confined states. Superlattices investigated contained n layers each of GaAs and AlAs in the [001] orientation. For n=4, an analysis of the self‐consistent charge distribution shows electron confinement in the AlAs region. The highest valence‐band state is always localized in the GaAs region giving a staggered band alignment for this superlattice. The calculated valence band offset is about 0.3 eV. The tendency towards nonstaggered band lineup is noted since Γ c 6(GaAs), which for n=2 superlattice lies above X c 6(AlAs) continues to shift down towards it when n is varied from 2 to 4. In large superlattices, both electrons and holes are confined in the GaAs region. We have also studied the stability of the ordered phases in epitaxially grown Ga1−x Al x As alloys. Our total energy calculations suggest that the ordered structure (GaAs)1–(AlAs)1 is favored over the disordered one. However, the ordered structure has a negative heat of formation (metastable) and segregation into constituents is suggested.