The high power operation of mid‐infrared quantum cascade lasers at temperatures up to T=320 K is reported. Gain at high temperature is optimized by a design combining low doping, a funnel injector, and a three‐well vertical transition active region. A molecular beam epitaxy grown InP top cladding layer is also used to optimize heat dissipation. A peak pulsed optical power of 200 mW and an average power of 6 mW are obtained at 300 K and at a wavelength λ=5.2 μm. The devices also operate in continuous wave up to 140 K.