The performance of any optoelectronic system and of infrared windows made from semiconductors is reduced by the large coefficient of reflection at each semiconductor‐free space surface, which has a typical value of about 30%. This paper reports the successful growth of multilayer antireflection coatings on GaAs using alternating layers of AlAs and GaAs. Bandwidths of 14% for a reflectivity of less than 13%, and 6% for a reflectivity of less than 7% were achieved, together with a minimum reflectivity of 1.3%. Model calculations suggest that these two structures can have reflectivities less than 10%, and 1% for these bandwidths under ideal conditions; the reasons for these discrepancies are explained. The results show that molecular beam epitaxy (MBE) has the potential for reproducible growth of antireflection coatings giving signal gains of 1.5 dB per surface at a given design wavelength.