Relative absorption cross sections for hydrogen peroxide vapor were measured over the temperature ranges 285--381 K for 230 nm≤λ≤295 nm and 300--381 K for 193 nm≤λ≤350 nm. The well-established 298 K cross sections at 202.6 and 228.8 nm were used as an absolute calibration. A significant temperature dependence was observed at the important tropospheric photolysis wavelengths, λ>300 nm. Measured cross sections were extrapolated to lower temperatures, using a simple model which attributes the observed temperature dependence to enhanced absorption by molecules possessing one quantum of O--O stretch vibrational excitation. Upper tropospheric photodissociation rates calculated using the extrapolated cross sections are about 25% lower than those calculated using currently recommended 298 K cross sections. ¿ American Geophysical Union 1988