A method for noninvasive ultrasound measurements of temperature distribution in solids is described and experimentally demonstrated in the estimation of an axial distribution of the temperature and the heat flux along a cementitious sample. It is further shown that by supplementing the ultrasound measurement with the surface temperature measurements, the entire volumetric distribution of the internal temperature inside of the solid sample and the corresponding heat fluxes can be reconstructed noninvasively. The unique capability for noninvasive characterization of the temperature and heat flux distributions in solids makes the developed approach particularly appealing for thermal characterization of solid components, structures, and containments of energy conversion processes, subsurface and nuclear applications, and other extreme environments, in which conventional sensors degrade quickly or their insertion is undesirable, difficult, or impossible.