A national mixed-methods study of English Serious Case Reviews (SCRs) was carried out to better understand the characteristics and circumstances of maternally perpetrated filicides, to compare these with paternally perpetrated cases, and to identify learning points for mental health professionals. Published reports for all SCRs of children in England dying as a result of abuse or neglect from 2011 to 2014 were subject to qualitative analysis using a system of layered reading and inductive thematic analysis, along with descriptive and comparative quantitative analysis. There were 86 deaths directly attributable to child maltreatment within the immediate family. The mother was the suspected perpetrator in 20. Twelve of the mother perpetrators were victims of domestic violence, while 15 of the father perpetrators were known to be perpetrators of domestic violence. Those deaths resulting from impulsive violence or severe, persistent cruelty are almost exclusively perpetrated by males, while those with an apparent intent to kill the child are slightly more likely to be perpetrated by mothers. Four key themes were identified through the qualitative analysis: domestic violence, maternal mental illness, separation and maternal isolation, and the invisibility of the child. These findings highlight the important role of domestic violence and its interaction with maternal mental health. Professionals working with mothers with mental health problems need to adopt a supportive but professionally curious stance, to be alert to signs of escalating stress or worsening mental ill-health, and to provide supportive and accessible structures for at-risk families.