This article examines the evidence on maltreatment in foster care, drawing on a critical review of research published in the USA, the UK and Australia. Few studies have reported on the extent of maltreatment in this setting and the evidence that does exist is inconclusive. The limited available evidence suggests that maltreatment may be reported for up to two per cent of children in foster care in any one year, but much depends on the definitions used and on local variation in thresholds for investigation. The article discusses the perpetrators and nature of this maltreatment and problems with substantiation, and highlights important gaps in the existing research. Copyright © 2013 John Wiley & Sons, Ltd. Key Practitioner Messages: It is important to distinguish allegations of maltreatment from those concerning poor standards of care. However, the boundary between the two may sometimes be unclear. Poor assessment and supervision of foster carers may increase the risk of maltreatment. Precipitate responses to allegations of poor standards of care, without a proper assessment of the balance of risks, may themselves be harmful to children's emotional wellbeing. ‘It is important to distinguish allegations of maltreatment from those concerning poor standards of care’