A process for alkylating the ortho-position of a phenol compound which comprises bringing a phenol compound containing at least one hydrogen atom at its ortho-position and an alcohol into contact with a catalyst in the gaseous phase, said catalyst being selected from the group consisting ofA. a mixture of iron oxide and silica in which the atomic ratio of Fe to Si is 100 : 0.03 - 200, andB. a mixture of iron oxide, silica and chromium oxide in which the atomic ratio of Fe to Si to Cr is 100 : 0.1 - 5 : 0.1 - 5.