Physical development in adolescence is one of the key aspects of the modern society’s well-being. Assessment of physical development in children and adolescents represents an essential component of the pediatric population health status estimation being a clear indicator of the impact of lifestyle, environment, and learningmprocess on the child’s body. The study was aimed to assess the dynamic changes of physical development indicators in the high school-age children in the Samara Region over a decade. The paper deals with the anthropometric data of physical development acquired in 2013 and 2023. A total of 476 children aged 14–16 years were examined (256 boys, 220 girls). Physical development assessment performed in the group of high school-age boys revealed significant changes. Boys of all ages examined in 2023 lagged behind their peers examined in 2013 in the number of individuals with harmonious physical development. Furthermore, a significantly greater number of children with disharmonious physical development due to excess body weight were revealed in 2023. The results yielded by assessing physical development in girls are slightly different: the today’s 14-year-old schoolgirls lag behind girls examined in 2013 in the size of population with harmonious physical development. The body height comparative analysis results have shown that the today’s schoolchildren do not lag behind their peers examined in 2013 in all gender-age groups (p > 0.05). A significant increase in the schoolchildrens’ body weight relative to 2013 is likely to result from the quarantine measures related to the COVID-19 pandemic, which made children stay at home for longer and reduced their physical activity.