To provide a method for producing an ortho-alkylated phenol from a phenolic compound and an alcohol in high selectivity.

An o-alkylated phenol compound is produced by reacting a phenolic compound of general formula (1) (R1, R2, R3, R4 and R5 are each independently H or a 1-10C straight or branched chain alkyl) with an alcohol in the presence of at least one kind of metal oxide selected from germanium oxide, molybdenum oxide, iron oxide, indium oxide and strontium oxide or in the presence of the above metal oxide and carbon dioxide under a condition to form a supercritical state or a subcritical state of the alcohol or the mixture of the alcohol and carbon dioxide.