The ethanol dehydration and subsequent ethylene oligomerization to short-chain olefins using catalysts based on ZSM-5 zeolite was studied in detail. P, Fe, and Ni were added by incipient wetness impregnation on zeolites with two SiO₂/Al₂O₃ molar ratios (50 and 80). The catalysts were characterized by N₂ adsorption–desorption, XRD, SEM–EDX, FTIR spectroscopy of adsorbed pyridine, and XPS techniques, while the catalytic activity was evaluated using an isothermal fixed-bed reactor. The impregnation of P, Fe, and Ni significantly improved the formation of the desired C₃₊ olefins (olefins having three or more C atoms). Particularly, the zeolite with SiO₂/Al₂O₃ molar ratio = 50 and impregnated with P, exhibited the highest selectivity (C₃₊ olefins > 45 wt% at TOS = 5 h) in comparison with the rest of the evaluated catalysts. On the contrary, catalysts with SiO₂/Al₂O₃ molar ratio = 80 showed lower selectivity to C₃₊ olefins, producing more side products (i.e. paraffins, aromatics and diethyl-ether).