Abstract In this Letter the electronic properties of double‐walled carbon nanotubes (DWCNTs) were studied by transmission measurements as a function of hydrostatic pressure up to 10 GPa. The energies of the optical transitions between the Van Hove singularities decrease with increasing pressure, which can be attributed to pressure‐induced hybridization and symmetry‐breaking effects. We observed a linear behaviour in the pressure‐induced shift of the optical transitions. This is in good agreement with previous studies on single‐walled carbon nanotubes (SWCNTs). magnified image High‐resolution TEM image of a bundle of DWCNTs (A), histogram of the number of walls (B), and diameter distribution for CNT samples plotted from 100 HRTEM images (C). (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)