Thermal conductivities of VNx/MgO(001) (0.76 amp;lt;= x amp;lt;= 1.00) epitaxial layers, grown by reactive magnetron sputter deposition, are measured in the temperature range 300 amp;lt; T amp;lt; 1000 K using time-domain thermore-flectance (TDTR). Data for the total thermal conductivity are compared to the electronic contribution to the thermal conductivity calculated from the measured electrical conductivity, the Wiedemann-Franz law, and an estimate of the temperature dependence of the Lorenz number L(T). The total thermal conductivity is dominated by electron contribution and varies between 13 W m(-1) K-1 at x = 0.76 and 20 W m(-1) K-1 at x = 1.00 for T = 300 K and between 25 and 35 W m(-1) K-1 for T = 1000 K. The lattice thermal conductivity vs x ranges from 5 to 7 W m(-1) K-1 at 300 K and decreases by 20% at 500 K. The low magnitude and weak temperature dependence of the lattice thermal conductivity are attributed to strong electron-phonon coupling in VN.