AimsBackground: In recent years, fathers have become increasingly involved in pregnancy and childcare and the concept of paternal perinatal mental illness (PMI) has gained research interest. There has been increased recognition of the impact of parenthood on the mental health of males, particularly in first time fathers where feelings of helplessness and marginalisation are common. Prevalence of paternal PMI is thought to be 10–16%, with higher risk demonstrated when their partner too experiences PMI. The importance of this topic was highlighted in the NHS long term plan, which recognised the disparity in service provision between males and females and the need to address this. Aim: To conduct a systematic review to establish the knowledge, beliefs, and experiences of males with PMI and whose partners had PMI, and to understand the barriers associated with help-seeking for paternal PMI.MethodsFive databases including EMBASE, Web of Science, Ovid MEDLINE, Scopus and PsycINFO were searched for qualitative studies investigating the experiences of males affected by PMI personally or through their partner's illness. The research question and inclusion criteria were determined using the PICOSS (population, intervention, comparison, outcome, setting, study design) method. 11 studies met criteria for inclusion and were appraised for quality using the Critical Appraisal Skills Programme and Joanna Briggs Institute Qualitative checklists. Evidence was synthesised using thematic analysis and study quality and risk of bias were assessed using the Assessing the Methodological Quality of Systematic Reviews (AMSTAR 2) checklist and Risk of Bias in Systematic Reviews (ROBIS) too.Results5 main themes and 17 sub-themes were identified, and demonstrated lack of knowledge and preparation for fatherhood, and distress and isolation experienced by males with PMI. Males were reluctant to seek help, and factors including stigma and lack of awareness regarding PMI and available support services were identified as barriers. The option to remain anonymous, flexibility of appointments and an emphasis on peer support were considered facilitators to engagement.ConclusionUnhelpful and potentially damaging stereotypes regarding masculinity and PMI still exist, prohibit help-seeking for PMI and promote the marginalisation of males in perinatal settings. Support for males with PMI is warranted but lacking, and effective communication and education regarding paternal PMI for both professionals and the public is needed to allow successful expansion of services to include males.