The emergence of 21st-century skills convinced educational institutions in modifying teaching styles, which lead to the introduction of blended, flipped, and personalized learning. Studies demonstrated present-day best practices, but none provided a practical assessment procedure. Thus, this study aimed to develop a tool in evaluating learning modules--the 21st-century e-Learning Module Assessment Tool. Identification of components for the instrument revealed the interrelating nature of blended, flipped, and personalized learning; hence, it considered nine components of 21st-century teaching instead of assessing the teaching styles separately. Content validity is established through expert evaluation while reliability is established through pilot testing. 21st-Century e-Learning Module Assessment Tool uses a 5-point scale to rate learning modules based on its compliance to the nine components of 21st-century teaching. The developed assessment tool is recommended to be used as standard in evaluating existing learning modules and a guide for future 21st-century learning modules.