This review summarizes the present status of physiologically based pharmacokinetic (PBPK) modeling and simulation (M&S) and its application in support of pediatric drug research. We address the reasons that PBPK is suited to the current needs of pediatric drug development and pharmacotherapy in light of the evolution in pediatric PBPK methodologies and approaches, which were originally developed for the purpose of toxicologic evaluation. Also discussed is the current degree of confidence in using PBPK to support pediatric drug development and registration and the key factors essential for robust results and broader adoption of pediatric PBPK M&S.