This communication presents a comparison of three values of third‐order nonlinear permittivity of &agr;‐quartz that have been obtained independently by three different methods. Each method produces a value of a different order of magnitude, in the range between 10−22and 10−20F/m, and with no uniformity in sign among them. This apparently represents the most pronounced conflict existing today among third‐order nonlinear electromechanical constants of quartz obtained from various sources. No explanation for the conflict is readily available.