Maternal mental illness is a growing public health concern. The impact of mental illness during the perinatal period (during pregnancy or up to one year after giving birth) can be considerable not only for mothers but also for their children, partners and wider family.Health visitors (qualified nurse or midwife who has undertaken specialist training in community public health) are in a unique position during the perinatal period to support mothers and their families. However, the type of support and its frequency in health visiting can vary. In addition, there is limited research that considers what factors may enable or hinder health visitors’ family-focused practice. This issue brief provides an overview of current health visiting practice in maternal mental health, places family-focused practice within the context of health visiting, and outlines future research developments.