The Nrxn1 +/- mouse is a novel strain (Lu H, et al. 2023. Cell Reports. 42:112714), which has not previously been studied for learning and memory performance. Our experiment trained 6-9 month-old male and female Nrxn1+/- and Nrxn1+/+ wildtype (C57BL/6J) mice for odour discrimination learning in an operant olfactometer with a sucrose reward for responding (licking) to the CS+ odour and no reward for responding to the CS- odour. Once the mice had met the criterion of 85% correct, they were tested in a reversal learning paradigm. The total errors made by the Nrxn1+/- mice and wildtype mice were analyzed in each phase of training (Introduction Task, Operant Odour Pair 1, Reversal of Odour Pair) and compared for genotype and sex differences. While there were no genotype differences in the number of errors in the initial operant tasks, there were significantly more errors on reversal learning in the Nrxn1+/- mice than in the wildtype controls. The study concludes that the Nrxn1+/- mice underperform in olfactory reversal learning tasks as they demonstrate a weaker cognitive flexibility to perform a reversal task efficiently. Following this experiment, we recommend a larger sample size to verify results as well as testing for age-related effects on reversal learning in the Nrxn1+/- mice.