The effect of the proximity of a bare barrier surface on the quantum efficiency of underlying GaAs/Al0.3Ga0.7As and In0.13Ga0.87As/GaAs quantum wells (QWs) is studied by low‐temperature photoluminescence. The quantum efficiency of the resonantly excited QWs diminishes with decreasing surface barrier thickness; the onset of the reduction in quantum efficiency of the InGaAs QW occurs for a barrier that is 50 A˚ thicker than for the GaAs QW. A simple model of carrier tunneling to the surface is formulated to explain the dependence of the quantum efficiency on surface barrier thickness and well width and height. This model shows good agreement with both sets of experimental data.