Background: Recently, school mobility was identified as a risk factor for psychotic symptoms in early adolescence. The extent to which this risk continues into late adolescence and the trajectories via which this risk manifests remain unexplored. Methods: Psychotic symptoms in 4,720 adolescents aged 18 were ascertained by trained psychologists using the Psychosis-Like Symptoms Interview. Mothers reported on sociodemographic factors (i.e., family adversity, ethnicity and urbanicity) from pregnancy to 4 years; child's involvement in bullying at age 6-7 years; residential mobility at 11 years and school mobility at 11-12 years. Young people reported on their friendships at 8 years, and antisocial behaviour and cannabis use at 15 years. Results: School mobility across childhood significantly predicted psychotic symptoms at 18 years (adjusted odds ratio = 2.15; 95% confidence intervals = 1.06, 4.40). Within path analysis, school mobility (ß = 0.183, p = 0.035), involvement in bullying (ß = 0.133, p = 0.013), antisocial behaviour (ß = 0.052, p = 0.004), cannabis use (ß = 0.254, p = 0.020) and female sex (ß = 0.420, p < 0.001) significantly predicted psychotic symptoms. Residential mobility (ß = 0.375, p < 0.001), involvement in bullying (ß = 0.120, p = 0.022) and poor friendships (ß = 0.038, p = 0.014) significantly predicted school mobility. Residential mobility indirectly increased the risk of psychotic symptoms via school mobility (ß = 0.069, p = 0.041). Conclusions: Children who move schools often are more likely to have experienced peer problems. School mobility, in turn, appears to be a robust marker for psychotic symptoms in late adolescence. Clinicians and teachers should consider school mobility as an important risk indicator for both peer problems and psychopathology.