Background: Prenatal stress has been shown to predict persistent behavioural abnormalities in offspring. Unknown is whether prenatal stress makes children more vulnerable to peer victimisation. Methods: The current study is based on the Avon Longitudinal Study of Parents and Children, a prospective community-based study. Family adversity, maternal anxiety and depression were assessed at repeated intervals in pregnancy and the postnatal period. Parenting, partner conflict and temperament were measured at preschool age. Peer victimisation was assessed using multiple informants (child, parent, teacher) at primary school age (between ages 7 and 10). Results: Prenatal severe family adversity and maternal mental health directly increased the risk of victimisation at school even when controlled for postnatal family adversity and maternal mental health, parenting, partner conflict and temperament. Effects were found to be independent of sources of information of peer victimisation. Partner conflict and maladaptive parenting also independently increased the risk of peer victimisation. Conclusions: Experiences in pregnancy may affect the developing foetus and increase vulnerability to be victimised by peers. Conflict between parents and their parenting further increase the risk of being victimised by peers at school. (Contains 4 tables and 1 figure.)