The electron‐beam‐pumped XeF laser operating on theB‐XandC‐Atransitions shows a strong temperature dependence. Fluorescence, gain, and laser output measurements in Ar/Xe/NF3and Ne/Xe/NF3mixtures are reported for temperatures from 300 to 600 K. Elevated temperatures cause stronger mixing between theBandCstates as well as among the vibrational levels within theBstate. Together with the higher ground‐state dissociation rate this leads to an improvement of theB‐Xlasing for 300k <T< 500 K, whereas theC‐Alaser emission ceases under these conditions.