By electron-beam lithography and wet chemical etching quantum boxes with a controlled shape as, e.g., a rectangular cross section, can be realized. We have fabricated quantum boxes with approximately constant widths of 50–60 nm and strongly varying lengths (150–80 nm). The luminescence of the structures shows a shift of the ground-state emission to higher energy as well as transitions between excited box states. By comparison with model calculations the changes of the emission spectra are related to the length quantization in the structures. ©1997 American Institute of Physics.