Involving and supporting the family members and caregivers of people with mental illness is essential to high-quality mental health services. However, literature suggests that there is a lack of engagement between family members and mental health nurses (MHNs). Lack of knowledge among MHNs is often cited as one of the main reasons for this lack of engagement. The aim of this review was to explore the knowledge, skills and attitudes that are required by MHNs to enable to them to work more effectively with families affected by mental illness. A literature based critical review was used to access and review 35 papers in order to extract concepts that could inform the design of eLearning materials to assist MHNs advance their knowledge in this area. Two overarching themes were identified; 'Mental health problems and the family' and 'Working with the family'. From these themes, the knowledge, skills and attitudes required to work more effectively with families are described. The findings from this review provide a descriptive account of the knowledge skills and attitudes that are required for effective family work. In addition, the review provides an empirical foundation for education programmes in the area. Highlights • Mental health nurses often lack the knowledge and skills to support families. • Well-designed education programmes increase knowledge, reduce stress and burden. • Education programmes need to prepare mental health nurses more effectively with families.