This article addresses an explanatory gap in global trends of religiosity: since around 2007, many countries have shown a decline in indicators of individual religiosity, such as the importance of God in life, religious self-identification, and ritual participation, while Muslim-majority societies have maintained stable and high levels of religiosity on these indicators. The article distinguishes this decline from secularization in the broader sociological sense, which includes the differentiation of public institutions from religious authority and the declining social authority of religion. It therefore does not deny that Muslim societies have experienced forms of institutional secularization; rather, it asks why individual, identity-based, and ritual religiosity has remained comparatively resilient in these societies. Critiquing a modernization-oriented account of secularization, which treats scientific progress and rationalization as linear causes of religious decline, the article argues that the impact of science on religiosity is context-dependent and shaped by cultural and social environments. Drawing on secondary data from the World Values Survey, the Arab Barometer, and findings from RASIC, it proposes a three-layered framework. The epistemic–textual layer highlights Islam’s capacities for reinterpretation and integration of new knowledge; the historical–institutional layer emphasizes memories of coexistence between religion and science and educational patterns that mitigate conflict; and the identity–cultural layer explains how rituals, language, meaning, and colonial experience foster cohesion and boundary-making.