The hyperpolarizabilities of benzene have been calculated using a free‐electron model for the π‐electron system. The first hyperpolarizability is identically zero. For the second hyperpolarizability only the components γzzzz; γxxxx; γyyyy; γzzxx; γzzyy; γxxyy are non‐zero. Some of these γ quantities show dispersion near the characteristic absorption band of the benzene molecule. The polarizability α of the π‐electron system also shows similer dispersion. Copyright © 1968 John Wiley & Sons, Inc.