In popular culture, converts to a new religion, especially Islam, are widely considered overly zealous. This is despite a lack of evidence for this view. But do converts to Islam have faith differently than their ‘born Muslim’ counterparts (non-converts)? Very little research has explored such differences. Consequently, this study compares Islamic religiousness, as measured by the Psychological Measure of Islamic Religiousness (Abu Raiya et al., 2008), between convert and non-convert US Muslims using a series of confirmatory and exploratory factor analyses. In our sample, Abu-Raiya et al.’s (2008) proposed factor structure showed poor model fit. Exploratory factor analyses provide evidence that Islamic religiousness of converts and non-converts differ in meaningful ways: converts have a simpler structure of religiousness than non-converts, and their beliefs are less directly aligned with their practices compared to non-converts. These findings suggest that converts and non-converts it seems they believe and practice Islam differently.