Processes for transalkylation of aromatic hydrocarbons is disclosed. The process includes introducing a feed stream comprising aromatic hydrocarbon compounds to a transalkylation zone. A water source is introduced to the transalkylation zone, the water source being in an amount to provide about 80 to about 120 wppm of water based upon the mass of the feed stream. The feed stream is contacted with a transalkylation catalyst in the transalkylation zone under transalkylation conditions comprising a transalkylation temperature of about 130° C. to about 230° C. in the presence of the water to provide a transalkylation reaction effluent.