Novel stimuli can be stressful for individuals with autism spectrum disorders (ASD), though repeated exposure can reduce this effect. In Cntnap2-/- and Shank3B+/− mouse models of ASD, novel background odors impaired behavioral target odor recognition but that deficit improved with training. To investigate the neural basis of this improvement, we used wide-field calcium imaging to measure olfactory bulb responses in Cntnap2−/− and Shank3B+/− mice and WT mice of either sex. Training with background odors enhanced both behavioral performance and neural discriminability of odor mixtures in both Cntnap2−/− and Shank3B+/− as well as WT mice. Naive Cntnap2−/− and Shank3B+/− mice showed greater trial-to-trial neural variability than WT mice, but training stabilized neural responses. Critically, training produced a widespread reduction in olfactory bulb responses to background odors in ASD models, but not in WT mice. Thus, despite similar behavioral improvements as WT mice, Cntnap2−/− and Shank3B+/− mice relied on ...