The selective formation of 6-tert-butyl-2-methoxynaphthalene is reported for the first time in the liquid phase alkylation of 2-methoxynaphthalene with tert-butanol over large-pore zeolites (maximum of 96% selectivity over H-MOR at 65% conversion). Over H-Y, which has been shown to be the most efficient catalyst in such a reaction in terms of activity, the main secondary reactions are the dialkylation, leading to bulky di-tert-butyl-2-methoxynaphthalene derivatives, and the demethylation of the methoxy group, giving mono- and di-tert-butyl derivatives of naphthol.