Sharp spectral features have been observed in the far-infrared spectra of Jupiter and Saturn as recorded by the Voyager spacecraft missions. These features, which occur very close to the S(0) and S(1) transition frequencies of H2, have recently been analyzed in detail by Gautier, Marten, Baluteau, and Bachet, but there has not been a fully satisfactory explanation for their origin. It is proposed here that the features, and particularly an absorption maximum at 350.5 cm−1, may be due to bound (H2)2 van der Waals dimers in the upper atmospheres of the giant planets.