Background and Purpose Schoolchildren with language difficulties experience more peer victimization compared to their typically developing (TD) peers. Whether these children also bully their peers (bully perpetration) more than TD children is unclear. Furthermore, little is known about peer victimization and bully perpetration among preschool children with language difficulties and how it may be related to different paths of language difficulties. This study aimed to investigate associations between language difficulties, peer victimization, and bully perpetration from preschool to school age as well as the risk of peer victimization and bully perpetration for children with different developmental paths of language difficulties and mild language difficulties compared to TD children. Method The sample was drawn from the Norwegian Mother, Father and Child Cohort Study. Participants with completed questionnaires at 3, 5, and 8 years of age ( = 22,628) were included. Paths between latent variables of language skills at 3, 5, and 8 years of age, peer victimization at 5 and 8 years of age, and bully perpetration at 8 years of age were examined with structural equation modeling. Logistic regression was used to investigate peer victimization and bully perpetration for predefined paths of language difficulties. Results Poor language skills at 3 and 5 years of age were associated with peer victimization at 5 years of age. Poor language skills at 5 and 8 years of age were associated with peer victimization and bully perpetration at 8 years of age. The association between poor language skills at 5 years of age and bully perpetration at 8 years of age was stronger for girls. Persistent paths of language difficulties at 3, 5, and 8 years of age showed the highest risk of peer victimization and bully perpetration. Conclusions Language difficulties are associated with peer victimization and bully perpetration. The risk of peer victimization and bully perpetration differs according to different developmental paths of language difficulties from preschool to school age.