Phenelzine sulfate crystallizes in the space group P21/c (#14) with a = 20.7418(15), b = 5.51507(5), c = 20.6038(11) Å, β = 109.5490(25)°, V = 2,221.06(9) Å3, and Z = 8 (Ẓ̣′ = 2) at 298 K. The crystal structure consists of supramolecular double layers of cations and anions parallel to the bc-plane. The inner portion of the layers consists of the charged parts of the cations and the anions, whereas the outer surfaces consist of phenyl rings, with van der Waals interactions between the layers. The sulfate anions stack along the c-axis. Each N–H acts as a donor to at least one sulfate O atom, and each O atom acts as an acceptor in at least one N–H···O hydrogen bond. The powder pattern has been submitted to the International Centre for Diffraction Data for inclusion in the Powder Diffraction File™ (PDF®).