Lymphoma incidence and survival in adolescent and young adult (AYA, defined as 15–39 years of age) and adult patients (>39 years) were assessed using Surveillance, Epidemiology, and End Results (SEER) data. From 2000 to 2014, 431 721 lymphoma cases were reported to SEER, 9% in AYA patients. In the AYA group, the highest age-adjusted incidence rate was for classical Hodgkin lymphoma [HL; 3·4 per 100 000 person-years; 95% confidence interval (CI), 3·38–3·49] followed by diffuse large B cell lymphoma (DLBCL; 1·56, 95% CI, 1·53–1·60) and for adults, it was plasma cell neoplasms (14·17, 95% CI, 14·07–14·27), DLBCL (13·86, 95% CI, 13·76–13·96) and chronic lymphocytic leukaemia (CLL; 13·19, 95% CI, 13·09–13·29). HL comprised 42% of lymphoma cases for AYAs, but only 4% in adults. The occurrence of DLBCL among AYAs and adults was similar, 18% and 20%, respectively. Twenty-eight percent of AYAs compared with 9% of adults presented with stage II disease, and 21% of AYAs compared with 10% of adults had B-symptoms. Extranodal disease was less common (33%) in AYAs than adults (59%). Overall, AYA patients with lymphoma have better 2- and 5-year relative survival rates (RSRs) compared to adults. When restricted to HL and DLBCL, RSR of AYA patients exceeds adult RSR.