Abstract Background Worldwide maternal mental illness poses a major public health issue. Supporting maternal mental health and family health is a core aspect of home visiting. Increasingly the benefits of family focused treatments to maternal mental illness are being recognised. However, there are few reliable and valid measures that attempt to assess this type of practice. Objectives To explore the psychometric properties of the Family Focused Mental Health Practice Questionnaire in a population of home visitors. Methods Home visitors (n = 230) from across a single region of the United Kingdom completed the Family Focused Mental Health Practice Questionnaire. Participants were all females, had a mean age of 44 years, and had an average of 11 years’ experience of home visiting. Exploratory factor analysis was used to explore the factor structure of the questionnaire in this population while Cronbach’s alpha was used to assess the internal consistency of questionnaire subscales. Results Exploratory factor analysis revealed a 3-factor solution where each factor contained at least three questionnaire items and had eigenvalues 1.0. Checks for internal consistency revealed that one factor was unsatisfactory (α < 0.6), which was subsequently discarded. A further exploratory factor analysis supported a 2 factor solution. The factors were named: professional influences on family focused practice and organisational influences on family focused practice. Cronbach’s alpha for the new scale was 0.949. Conclusion As home visitors play a key role in supporting parents who have mental illness and their families, it is important to assess their practice using a reliable measure. Our psychometric evaluation has created a more valid, reliable and concise measure that can be used to examine home visitors’ family focused practice.