Although gastrointestinal polyps are more common in the first decade of life than during adolescence, underlying genetic polyposis syndromes are more likely in adolescents. In the past decade, the discovery of gene defects associated with polyposis syndromes has improved classification of these disorders, assisted in the stratification of cancer risk, and permitted more precise diagnosis. Genetic testing is now clinically available for the gene defects that occur in familial adenomatous polyposis coli, Peutz-Jeghers syndrome, Cowden syndrome, and juvenile polyposis syndrome. This review outlines clinical features, genetics, and management strategies for the major polyposis syndromes that affect adolescents.