Aim To measure the influence of a mental health training module on the therapeutic optimism of primary care advanced nurse practitioner (ANP) students. Method A pre and post-test evaluation of the influence of a mental health training module on the therapeutic optimism of ANP students in primary care was conducted. Students completed an adapted Elsom Therapeutic Optimism Scale (ETOS), before and after completing the module, and the ETOS scores were analysed. Results Therapeutic optimism scores were higher following module completion. Conclusion Up to 70% of UK mental health presentations are assessed and managed in primary care. Many patients will be assessed, diagnosed and treated by ANPs. This evaluation shows that a marked increase in therapeutic optimism occurs after module completion.