Ru nanoparticles supported on tungstated zirconia (WZr) were prepared and used for the catalytic hydrodeoxygenation of guaiacol to deoxygenated hydrocarbon fuels. The tuning of tungsten, from 5 to 20 wt%, adjusted the number of acid sites on the tungstated zirconia and the size of the Ru nanoparticles. The optimum fraction of tungsten was determined for the optimum hydrodeoxygenation activity. The conversion of guaiacol reached a maximum of 96.8% for 10 wt% of tungsten. Increasing the tungsten fraction increased the number of acid sites and the dispersion of Ru, but the formation of tungsten oxide (WOx) particles with too large fraction of tungsten inhibited the formation of smaller Ru nanoparticles, thus reducing the catalytic activity.