Pharmacokinetic (PK) modeling is essential in pediatric drug development, offering insights into drug behavior in children. Two primary approaches, population pharmacokinetics (PopPK) and physiologically based pharmacokinetic (PBPK) models, serve distinct purposes. PopPK models use statistical methods to analyze drug data from various individuals, focusing on population-level variability and factors like age and weight. These models guide dosing by predicting drug concentrations and minimizing adverse effects, especially important in vulnerable populations such as children. PBPK models, on the other hand, are mechanistic and simulate physiological processes affecting drug absorption, distribution, metabolism, and excretion. They integrate physiological and compound-specific data to predict drug behavior under different conditions, supporting dose scaling and formulation decisions. Both approaches contribute significantly to pediatric drug development. PopPK models help optimize dosing regimens and reduce clinical trial invasiveness, while PBPK models aid in understanding age-related pharmacokinetic changes and support regulatory submissions. Together, they enhance the development of safe, effective, and age-appropriate therapies, improving pediatric patient outcomes.