Cryobaric (11–100 K and 300 K, 0–65 kbar) measurements of photoluminescence in GaAs/AlxGa1−xAs multiquantum well structures are described. Results on a narrow‐well (38 A˚ wide) structure exhibitingbothquantum well and bulk GaAs emission (from a thick buffer region) allow direct comparison of the two for the first time. We find that transitions between &Ggr;‐derivedn=1 confined levels have the same pressure coefficient, within ±0.2 meV/kbar, as the bulkE0gap, 11.4 meV/kbar. An interaction betweenn=1 electron states and a state 35–40 meVbelowtheX‐conduction minima is observed within the pressure‐induced &Ggr;‐Xcrossover region for our narrow‐well sample. The proposed origin of the latter state is residual interface impurities.