There remains some uncertainty about the magnitude of the associations between elevated blood pressure (BP) in childhood or adolescence and cardiovascular morbidity and mortality in adulthood. We summarized evidence on the long-term impact of elevated BP in childhood or adolescence on cardiovascular morbidity and mortality in adulthood. PubMed and Embase databases were searched up to August 1, 2019, and retrieved studies were reviewed manually. Our systematic review included all eligible prospective cohort studies on the associations between BP status in childhood or adolescence and intermediate markers or hard outcomes of cardiovascular disease in adults, including high pulse wave velocity, high carotid intima-media thickness, left ventricular hypertrophy, and cardiovascular disease (fatal and nonfatal) and total mortality. A total of 19 articles were finally included, and 12 could be synthesized by meta-analysis. Elevated BP in childhood or adolescence was significantly associated, in adulthood, with high pulse wave velocity (3 articles, N=3725; pooled odds ratio [OR], 1.83 [95% CI, 1.39–2.40]); high carotid intima-media thickness (2 articles, N=4152; OR, 1.60 [95% CI, 1.29–2.00]); and left ventricular hypertrophy (2 articles, N=3019; OR, 1.40 [95% CI, 1.20–1.64]). Additionally, our systematic review also shows evidence of associations of elevated BP in youth with cardiovascular disease and mortality in adulthood. In conclusion, our systematic review and meta-analysis confirms that elevated BP in childhood or adolescence is associated with several intermediate markers and hard outcomes of cardiovascular disease in adulthood. These findings emphasize the importance for children and adolescents to have their BP within normal values.