In an attempt to discover an explanation of the anomalous positive temperature coefficients of quadrupole resonance frequencies which are occasionally observed, the vibrational dependence of gas-phase quadrupole coupling coupling constants of simple molecules are reviewed and the origin of the vibrational dependence is discussed. It is concluded that intramolecular vibrations can give rise to both positive or negative contributions to the overall temperature dependence with about equal probability and that there is no need to postulate unusual vibrational modes or unusual bonding situations to explain the observed temperature coefficients.