High control of (110) oriented GaAs/Al0.3Ga0.7As quantum wells is very important for the growth of optimized T‐shaped GaAs/AlGaAs quantum wires. We investigate theoretically and experimentally 20–200 Å wide (110) oriented GaAs quantum wells grown on (110) oriented substrates and cleaved edges. Photoluminescence transition energies are found to be in good agreement with theory for all well widths. The mean well width is controllable to 1 monolayer accuracy and an effective well width fluctuation of 3.7 Å is derived from the photoluminescence linewidths. The growth rate calibration of the aluminum content of the barrier material agrees within 1% with an estimate from the bound exciton emission of (110) Al0.3Ga0.7As epilayers.