Background: This is the first national study on trends in cancer survival and mortality for children and young adolescents in the Netherlands including unique information on stage at diagnosis. Methods: All neoplasms in patients <18 years, diagnosed between 1990 and 2015 (N = 14,060), were derived from the Netherlands Cancer Registry. Cohort and period survival analyses were used to estimate observed survival (OS). Time trends in OS and mortality rates were evaluated by parametric survival models and average annual percentage change, respectively. Results: Between 1990 and 2015, 5-year OS and 10-year OS of childhood and young adolescent cancer have improved significantly by 9 percent points, reaching 81% and 78%, respectively. Favourable trends in survival were observed for all age groups and most diagnostic (sub)groups, being particularly pronounced for advanced disease. Non-Hodgkin lymphomas Ann Arbor stage III, metastatic neuroblastomas (age ≥18 months) and Ewing bone sarcomas showed significant improvements in 5-year OS. Compared with 1990–99, the risk of dying within five years of diagnosis was decreased significantly during 2000–09 (hazard ratio [HR] = 0.8) and 2010–15 (HR = 0.6), after adjustment for age, gender and follow-up time. Nonetheless, the prognosis of young patients suffering from central nervous system tumours, neuroblastoma and osteosarcomas remained modest, with 5-year OS <70% and 10-year OS <65%. Childhood and young adolescent cancer mortality decreased by an average of 2.0% annually between 1990 and 2018. Conclusions: Significant progress has been realised in the prognosis of childhood and young adolescent cancer in the Netherlands since the 1990s. Survival improvements were especially evident for patients with advanced stages and were also reflected in the declining mortality rates.