The gas phase hydrodeoxygenation (HDO) of guaiacol, as a model compound for pyrolysis oil, was tested on a series of novel hydroprocessing catalysts – transition metal phosphides which included Ni₂P/SiO₂, Fe₂P/SiO₂, MoP/SiO₂, Co₂P/SiO₂ and WP/SiO₂. The turnover frequency based on active sites titrated by the chemisorption of CO followed the order: Ni₂P>Co₂P>Fe₂P, WP, MoP. The major products from hydrodeoxygenation of guaiacol for the most active phosphides were benzene and phenol, with a small amount of methoxybenzene formed. Kinetic studies revealed the formation of reaction intermediates such as catechol and cresol at short contact times. A commercial catalyst 5% Pd/Al₂O₃ was more active than the metal phosphides at lower contact time but produced only catechol. A commercial CoMoS/Al₂O₃ deactivated quickly and showed little activity for the HDO of guaiacol at these conditions. Thus, transition metal phosphides are promising materials for catalytic HDO of biofuels.