The effects of free‐carrier broadening on luminescence linewidths in InGaAs‐InP quantum wells (QW’s) are demonstrated using Schottky barrier depletion and magnetic field quantization of the conduction‐band‐energy levels. After removal of free‐carrier broadening, linewidths of 5 meV for 100‐A˚, and 3.5 meV for 150‐A˚ QW’s grown by metalorganic chemical vapor deposition are obtained. Widths of 3.4 meV for a 110‐A˚ QW grown by molecular beam epitaxy (MBE) on ann+substrate, and only 2.0 meV at 6.2 T for a similar MBE sample grown on a semi‐insulating substrate are also reported.