By using transient-adsorption spectroscopic techniques, we discovered extraordinarily long-lived hot electrons in degenerately doped molybdenum oxides with surface plasmon resonance in the visible and near-infrared region. This finding provides new insights for the development of the new plasmonic photo-catalysts. Display omitted Plasmon-induced hot electrons offer unique advantages in solar-light-driven chemical reactions. Noble metal nanostructures have been the most studied plasmonic materials, but the hot electron lifetime is extremely short. Here, we have discovered extraordinarily long-lived hot electrons in degenerately doped molybdenum oxides with surface plasmon resonance in the visible and near-infrared region. Their lifetime is nanosecond-scale, which is enhanced by 4 orders of magnitude compared to their noble metal counterparts. Such a property is ascribed to the quasi-metallic feature of molybdenum oxides driven by hydrogen dopant-induced bandgap trap states, in which the electron–phonon scattering is dominant over the ultrafast electron–electron scattering in the decay dynamics of hot electrons. The plasmonic dye oxidation and hydrogen evolution are explored without the coupling of semiconductors, providing a viable way towards expanding the candidates for direct plasmonic photocatalysis.