This study evaluates the 10th-grade Din va Zendeghi textbook, which is used in Iranian high schools to teach Islamic education, using Masuhara’s (2013) framework for pedagogical content analysis. The objective was to examine the textbook’s goals and teaching/learning activities and to assess the extent to which these activities align with its stated educational philosophy—one that emphasizes moral development, rational inquiry, and student-centered learning grounded in Islamic teachings. The analysis was conducted in two stages: an external evaluation, which focused on introductory messages addressed to teachers and students, and an internal evaluation, which examined selected teaching/learning activities in terms of design, cognitive demand, and educational purpose. To ensure and guarantee the scientific reliability and trustworthiness of the analysis, two experienced religious education teachers independently reviewed 20% of the data and confirmed the researchers’ assessments. The findings indicate a high degree of alignment between the textbook’s intended objectives and its teaching/learning activities. The analysis was conducted in two stages: an external evaluation, which focused on introductory messages addressed to teachers and students, and an internal evaluation, which examined selected teaching/learning activities in terms of design, cognitive demand, and educational purpose. These activities include scriptural analysis, personal reflection, moral reasoning, and experiential engagement—all of which contribute to fostering a coherent Islamic worldview and the development of ethical agency among adolescent learners. Several educational implications are proposed at the end.