ObjectiveReligious/spiritual (R/S) growth is a core domain of posttraumatic growth (PTG). However, research on R/S growth following disasters has over‐relied on retrospective self‐reports of growth. We therefore examined longitudinal change in religiousness/spirituality following two disasters.MethodReligious survivors of Hurricanes Harvey (Study 1) and Irma (Study 2) completed measures of perceived R/S PTG, general religiousness/spirituality (“current standing”‐R/S PTG), and subfacets of religiousness/spirituality (spiritual fortitude, religious motivations, and benevolent theodicies). In Study 1, 451 participants responded at 1‐month and 2‐month postdisaster. In Study 2, participants responded within 5‐days predisaster and at 1‐month (N = 1,144) and 6‐months postdisaster (N = 684).ResultsIn both studies, perceived R/S PTG was weakly related to longitudinal increases in general religiousness/spirituality and in most of its subfacets, but reliable growth in any R/S outcome was rare. Additionally, Study 2 revealed evidence that actual change in psychological well‐being is associated with actual (but not perceived) R/S PTG, but disaster survivors tend to exhibit declines in their religiousness/spirituality, spiritual fortitude, and religious motivations.ConclusionsResults suggest disaster survivors are only modestly accurate in perceiving how much positive R/S change they experience following a disaster. We discuss implications for clinical practice, scientific research, and empirical and conceptual work on PTG more broadly.