The paper analyses children's experiences of (in)security in cases of post-separation stalking and asks how children can be safeguarded under such circumstances. Children are at particular risk when the family is stalked by the biological father or stepfather. This qualitative study draws on data collected from 13 children using three different methods: therapeutically-oriented group sessions, interviews with the children and a series of ten mother and child therapy sessions. Supplementing these data are insights gained from interviews with 18 women/mothers, the main targets of the stalking. The analysis of the narratives distinguishes three overlapping forms of security - eroded, lost and reconstructed - in which the degree of trust and extent of knowledge are the main elements. Children feel insecurity to different degrees and experiences of (in)security may vary even from child to child in the same family. The findings highlight the crucial importance of considering a child's relationship to his or her mother, siblings and trusted adults when intervening in stalking. Loved ones, day care and school staff, and social welfare workers have a significant role to play in reconstructing and strengthening children's security. The study suggests that this can be done through 'safety talk' with a mother and her children. Copyright © 2015 John Wiley & Sons, Ltd. Key Practitioner Messages In cases of post-separation stalking of the family, children's security can appear in three forms: eroded, lost and reconstructed., Feelings of insecurity vary and can appear to differing degrees within the same family., It is important in safeguarding children to lighten the burden that they take upon themselves of reconstructing security for themselves and their loved ones., Practitioners can play a significant role by providing space for and facilitating 'safety talk' between children and their mothers.