Strain‐induced effects in quantum wells of InAsxP1−x/InP, InxGa1−xAs/InP, and InxGa1−xAs/ In0.52Al0.48As on (111) InP substrates are investigated. The strain induces a large piezoelectric field in these structures, and causes a large change in their energy band edges. Consequently the band structure of the quantum wells is dramatically modified, and the dependence of interband transition energies on alloy composition is different from that of quantum wells on (100) substrates. Moreover, a larger critical layer thickness is found for the quantum wells studied. ©1995 American Institute of Physics.