Background Posttraumatic growth (PTG) is increasingly recognized as an important psychosocial phenomenon, but few studies have evaluated the longitudinal course of PTG. This study identified courses of PTG over a 2‐year period in a contemporary, nationally representative sample of U.S. military veterans, and examined sociodemographic, military, trauma, medical, and psychosocial predictors of PTG course. Methods Data were based on a Web‐based survey of a nationally representative sample of 1,838 U.S. veterans who reported at least one potentially traumatic event and provided data at two time points (October–December 2011 and September–October 2013). Results Five different courses of PTG were identified—Consistently Low (33.6%), Moderately Declining (19.4%), Increasing PTG (16.8%), Dramatically Declining (15.7%), and Consistently High (14.5%). More than half (59.4%) of veterans who reported at least “moderate” PTG maintained that level of PTG 2 years later. Posttraumatic stress disorder symptoms, medical conditions, purpose in life, altruism, gratitude, religiosity, and an active reading lifestyle predicted maintenance or increase in PTG. Conclusions PTG has a heterogeneous course and is not only common, but can persist over time especially in the presence of posttraumatic stress and certain psychosocial factors. Clinicians and researchers should consider the personal growth that can result from trauma and help trauma survivors find ways to maintain this growth over time.