The achievement of room‐temperature (300 °K) operation of Ga(1−x)AlxAs‐GaAs double‐heterostructure lasers with active layers of quantum‐well dimensions ∼200 A˚ thick is reported. These devices are grown by metalorganic chemical vapor deposition and exhibit pronounced effects in the spectral and lasing characteristics that are related to the small active region thickness and are the first such effects observed for DH lasers in the GaAlAs‐GaAs system.