The adsorption of aqueous solutions of BTEX (benzene, B; toluene, T; ethyl benzene, E; and xylenes, X) on hydrophobically modified zeolite was investigated. Multicomponent kinetics and equilibrium studies were carried out using a batch system. Furthermore, a mathematical model was studied that considers the mass transfer kinetics in a fixed-bed adsorption system. The influences of external mass transfer as well as the constant adsorption equilibrium and intraparticle diffusion resistance on breakthrough curves were evaluated. The adsorption kinetics was adjusted to the homogeneous diffusion model. The breakthrough times of the BTEX compounds increased with an increase in the bed height of the adsorbent and decreased with an increase in the flow. The mathematical model and numerical methodology that were applied represented the data of the present adsorption process with good accuracy.