This dissertation explores the concept of ‘integral’ in the context of Catholic Social Teaching and its crucial methodological role in developing this rich doctrinal tradition. It examines the concept’s historical evolution and philosophical underpinnings, drawing from the influence of Jacques Maritain’s Integral Humanism (1936). The research investigates the implicit and explicit use of the term ‘the integral’ in Catholic Social Teaching’s pre-Vatican II and Vatican II eras. Subsequent chapters analyse the concept’s significance in the social teachings of Pope Paul VI, John Paul II, Benedict XVI, and Francis, highlighting its role in promoting a holistic vision of development that encompasses the spiritual, material, and ecological dimensions. The significance of this research lies in shedding light on the capacity of Catholic Social Teaching to develop in meeting new social challenges while remaining consistent with its precedent. To this end, the concept, it is argued, plays a designative, hermeneutical, phenomenological, and normative role. In light of the concept’s ambiguity and complexity, seven connotations of the term are identified: transcendental anthropology, epistemological coherence, historical continuity, social cooperation, mutually constitutive and comprehensive interconnectedness, wholeness, and authenticity.