Childhood obesity has emerged as one of the most pressing public health challenges of the 21st century, affecting millions of children worldwide. The condition is driven by a complex interplay of biological, environmental, and behavioral factors. Among the most influential are dietary patterns, sedentary lifestyles associated with prolonged screen time, and declining levels of physical activity. This article explores the role of these three critical factors in the development of childhood obesity, highlights their long-term health consequences, and suggests evidence-based strategies for prevention and management.