Background Perinatal mental health problems affect approximately 20% of women.The most common condition is postnatal depression; however, many women do not seek help. Aims To identify and synthesise evidence on factors that enable or prevent help-seeking in women with depressive symptoms in the postnatal period. Methods A qualitative systematic review was conducted using electronic databases and pre-determined eligibility criteria. Findings Thematic synthesis of the included studies (n=4) identified the following themes: the influence of healthcare services, the influence of others and the influence of women themselves. Help-seeking was shaped by women's ability to recognise their symptoms, the reactions (experienced or anticipated) of others and the organisation of services. Conclusion An improved interface between maternity and mental health services and enhanced health professional interactions are needed. However, meaningful change may require empowering women's self-assessment and public health messages to improve understanding of postnatal depression.