We examined associations between overall posttraumatic stress disorder (PTSD) symptoms, symptom clusters of PTSD (reexperiencing, avoidance, dysphoria, and arousal), and relationship adjustment cross sectionally and longitudinally using self‐report measures from a dyadic sample of U.S. National Guard soldiers from the Iraq war and their intimate partners (N = 49 couples). Results of multilevel modeling revealed that Time 1 PTSD symptom severity significantly predicted lower relationship adjustment as rated by partners at Time 2 after controlling for baseline relationship adjustment (β = −.20, p = .025). Total PTSD symptoms did not significantly predict soldiers' ratings of relationship adjustment at Time 2. For soldiers, the PTSD symptom cluster of dysphoria was uniquely and significantly related to relationship adjustment ratings both at Time 1 and at Time 2, controlling for Time 1 adjustment. For partners, none of the soldiers' PTSD symptoms clusters was uniquely associated with Time 1 relationship adjustment or with change in adjustment over time. In contrast, findings regarding the effect of relationship adjustment on changes in PTSD over time found that Time 1 relationship adjustment was not associated with changes in PTSD symptoms at Time 2.