Optical spectra and luminescence decay curves were measured for thulium-doped ${\mathrm{YVO}}_4$ , ${\mathrm{GdVO}}_4$ , and ${\mathrm{LuVO}}_4$ single crystals as a function of temperature in the $300–670\mathrm{K}$ temperature region. In spite of structural similarity, the three systems studied display significantly different transition intensities and nonradiative relaxation rates. It was found, in particular, that the peak value of the pump band absorption intensity diminishes by about 30% for $\mathrm{Tm}\text{:}{\mathrm{YVO}}_4$ and $\mathrm{Tm}\text{:}{\mathrm{GdVO}}_4$ , and the effective emission cross section for the laser transition of ${\mathrm{Tm}}^{3+}$ diminishes by a factor of 2 roughly when temperature increases from 300 to $500\mathrm{K}$ . An unusually small quantum efficiency of the upper laser level in $\mathrm{Tm}\text{:}{\mathrm{LuVO}}_4$ has been derived from the analysis of luminescence decay curves.