The emission spectra of thermally stimulated surface plasmon polaritons (thermally stimulated surface plasmon polaritons) and a blackbody have been analyzed and compared, and the temperature dependence of these spectra has been studied. It has been found that the total energy of the entire ensemble of surface plasmons is proportional to the cube of temperature and their spectrum is red-shifted from the blackbody spectrum. It has been shown that the spectrum of thermally stimulated surface plasmon polaritons obeys the Wien’s displacement law, yet with another constant. The fraction of the photon energy of the conducting layer transferred to the surface plasmons has been estimated. It has been demonstrated numerically by the example of a gold layer that this fraction can exceed 10% for a layer thickness of less than 1 mm. © 2016, Pleiades Publishing, Ltd.