We evaluated the differences in higher systolic blood pressure (SBP) between boys and girls in a longitudinal adolescent cohort. Results showed that although boys have a 19% relative increase in the risk of higher SBP annually between the ages of 13 and 17 years, girls do not experience the same risk increase. Among both boys and girls, being overweight increases the likelihood of high SBP almost 3-fold, and every 5 additional hours of "screen time" (television viewing, video game playing, Internet use) is associated with a 4% relative increase in the likelihood of higher SBP levels. For every 5 additional sports-related or other active behaviors over a 7-day recall, there was an 8% relative reduction in high SBP risk. Annual blood pressure assessment in teens that continues into adulthood may facilitate early detection of adult hypertension. Weight control, increased physical activity, and reduced screen time may reduce the likelihood of higher SBP levels developing in adolescents.