High-temperature stability of lasing wavelength of GaAsSb/GaAs quantum well (QW) lasers grown by metal-organic vapor phase epitaxy will be demonstrated. According to the best of our knowledge, this is the first trial of using triethylgallium (TEGa) as the precursor to grow QW at low temperature (525°C). The lasing wavelength ranges from 1117 to 1144 nm and varies with temperature (dλ/dT) from 0.24 to 0.287 nm/K. These values are lower than other previously reported results. The QW grown at high temperature (600°C) by using trimethylgallium (TMGa) is also examined. The lasing wavelength is 1125.6 nm at room temperature and dλ/dT is 0.36 nm/K, which is higher than those lasers grown at lower temperature.