In this letter, we report the high-temperature stability of a lasing wavelength in GaAsSb/GaAs quantum-well (QW) lasers grown by metal-organic vapor phase epitaxy. To the best of our knowledge, this is the first successful use of triethylgallium (TEGa) as the precursor to grow GaAsSb/GaAs QW at low temperature (525 °C). The lasing wavelength ranges from 1117 to 1144 nm and varies with temperature λ/dT from 0.24 to 0.287 nm/K. These values are lower than those of other results reported previously. The QW grown at high temperature (600 °C) using trimethylgallium (TMGa) is also examined. The lasing wavelength is 1125.6 nm at room temperature, and dλ/dT is 0.36 nm/ K; the latter value is higher than those grown at lower temperature.