This article examines the reconstruction of Islamic epistemology through the integration of reason (al-‘aql) and revelation (al-wahy) in Harun Nasution’s thought and its relevance to contemporary Indonesian Islam. The enduring divergence between rational and textual methodologies in Islamic scholarship is the impetus for this research, as this division has fostered dogmatic religious understandings and a lack of intellectual advancement. This study employs a qualitative library research approach using philosophical, historical-intellectual, and epistemological analyses of Harun Nasution’s major works and related scholarly literature. The research indicates that Harun Nasution established a comprehensive epistemological structure that designates revelation as the fundamental basis for truth, while granting intellect a vital and context-dependent function in interpretation. This framework is further reconstructed into an integrative-transformative model encompassing textual (bayani), rational (burhani), spiritual (irfani), and empirical dimensions. The study argues that such an epistemological model remains highly relevant in addressing contemporary challenges in Indonesian Islam, including religious radicalism, digital religious disruption, and the crisis of religious authority. The main contribution of this article lies in the formulation of an integrative-transformative Islamic epistemology that provides a theoretical foundation for developing a moderate, rational, and progressive Indonesian Islam