New mothers with severe mental illness (SMI) frequently experience significant difficulties in caring for their babies. There are no structured, evidence-based interventions that guide health professionals to help these women improve early parenting. The extensively researched and effective Triple P Positive Parenting Programme has recently been expanded to families with children less than 1 year old, which provides an opportunity to develop the intervention for women with severe postnatal mental illness. This study explored the views of mothers with SMI about the acceptability and feasibility of Baby Triple P (Baby TP) in the setting of a psychiatric Mother and Baby Unit (MBU). An 88-item Q-sort was conducted with a purposive sample of 15 mothers using Q-methodology. Three main factors were identified: 'what we need', 'what we want' and 'we can do it'. A consensus was noted with general agreement about the benefits of Baby TP, and suitability of the MBU environment to accommodate Baby TP. Baby TP was viewed as an acceptable and feasible parenting intervention and deemed positive and non-stigmatising. Mothers requested more staff awareness and knowledge about the programme so that they were supported in learning and generalising skills.