This longitudinal study examined the course and bidirectional relation between posttraumatic distress and posttraumatic growth (PTG). A sample of Israeli ex-prisoners of war and matched controls were followed over 17 years. Participants’ posttraumatic stress disorder (PTSD), depression, and anxiety symptoms were measured at three time-points. PTG was assessed twice. Applying an autoregressive cross-lagged modeling strategy, initial PTSD predicted subsequent PTG above and beyond PTG stability, but not vice versa. Cross-lagged relations of PTG to depression and anxiety were not significant. Moreover, analysis of PTG trajectory revealed that individuals with PTSD reported higher PTG levels across times than those without PTSD. Thus, growth is facilitated and maintained by endorsement rather than absence of PTSD. The findings are discussed in the context of the illusionary versus adaptive notion of PTG.