The relationship between school achievement and peer harassment was examined using individual and peer characteristics as mediating factors. The sample consisted of adolescents age 12-15 years (n = 4,111) drawn from the Canadian National Longitudinal Survey of Children and Youth, which is a stratified random sample of 22,831 households in Canada. When factors related to achievement and harassment were considered simultaneously, disruptive behaviour problems and peer interactions were found to mediate the link between achievement and harassment, chi[superscript 2](32) = 300.00, p less than 0.001. These results suggest that adolescents who are harassed by their peers are at risk of experiencing poor school achievement if they exhibit disruptive behaviour problems and poor peer interactions. Implications for school psychologists are presented. (Contains 1 figure.)