We describe room‐temperature 2.78 μm AlGaAsSb/InGaAsSb multiquantum well lasers. Pulsed laser operation was observed at 15 °C with a threshold current of 1.1 A (10 kA/cm2), and a maximum power output of 30 mW, and a maximum differential quantum efficiency of 9%. Lasers operated pulsed up to 60 °C with a characteristic temperature of 58 K over the range of 0–40 °C. To date, 2.78 μm is the longest emission wavelength for a room‐temperature III–V laser.