The conversion of guaiacol, a prototypical compound representative of lignin-derived pyrolysis bio-oils, was catalyzed by Pt/Al2O3 in the presence of H-2 at 573 K. The conversion took place with a high selectivity for aromatic carbon-oxygen bond cleavage relative to the accompanying methyl group transfer reactions. This oxygen removal was not observed in the absence of H-2 as a co-reactant. Products that were formed by methyl-group transfer match those produced in the conversion catalyzed by zeolite HY, which was not active for oxygen removal reactions.