The invention provides an efficient process for producing alkylated aromatic compounds such as cumene in a compact reactor. The invention also provides a process for producing phenol which includes a step of producing cumene by the above process. The process for producing alkylated aromatic compounds of the invention includes feeding raw materials including an aromatic compound and an alcohol in a gas-liquid downward concurrent flow mode to a fixed-bed reactor packed with a solid acid catalyst thereby to produce an alkylated aromatic compound, wherein the raw materials are fed to the reactor in a stream of a gas, and the reaction gas flow rate defined by the equation below is not less than 0.05 at an entrance of a solid acid catalyst layer: ρg·ug·[ρair·ρwater/(ρg·ρl)]1/2(kgm−2s−1).