Deception is a common phenomenon in everyday life, yet some people generally lie more than others and some people consider lying more acceptable than others do. Current knowledge about lie acceptability across development or about the individual differences in emotion or personality which shape it is still in an incipient stage. We aimed to expand this emerging body of knowledge by investigating lie acceptability across three educational stages (primary school, middle school and high school) in a sample of 821 children and adolescents, ages 7 to 18. We also examined several predictors of lie acceptability assessed with the Behavioural Assessment System for Children and Adolescents (BASC): anxiety, sensation seeking, social desirability, attitudes towards school and teachers, and relationships with peers and parents. Lower anxiety and lower sensation seeking predicted middle school children's reduced lie acceptability. We showed that positive attitudes towards school and teachers predicted lower lie acceptability for primary and middle school children, but were not significant predictors for high school children. For middle school children, better peer relationships also predicted lower lie acceptability. This suggests that various predictors contribute differently to shaping lie acceptability across development, which can prove instrumental in designing age-appropriate interventions to reduce deceptive behaviour.