The relation between TV viewing and posttraumatic stress disorder (PTSD) is controversial; prior work focused exclusively on whether TV viewing of disaster events constitutes a traumatic stressor that causes PTSD. This study evaluates a possible bidirectional relation between PTSD and TV viewing in community-dwelling women. Data are from the PTSD subsample of the Nurses’ Health II study, an ongoing prospective study of women aged 24-42 years at enrollment and who have been followed biennially (N = 50,020). Trauma exposure and PTSD symptoms (including date of onset) were assessed via the Brief Trauma Questionnaire and the Short Screening Scale for DSM-IV PTSD. Average TV viewing was reported at 5 times over 18 years of follow-up. Linear mixed models assessed differences in TV viewing patterns by trauma/PTSD status. Among women with trauma/PTSD onset during follow-up (N = 14,374), linear spline mixed models assessed differences in TV viewing patterns before and after PTSD onset. Women with high PTSD symptoms reported more TV viewing (hours/wk) compared to trauma-unexposed women at all follow-up assessments (? = 0.14, SE = 0.01, p < .001). Among the women who experienced trauma during follow-up, significant increases in TV viewing (hours/day) prior to onset of high PTSD symptom levels were evident (? = 0.15, SE = 0.02, p < .001). TV viewing following trauma exposure may be a marker of vulnerability for developing PTSD and also a consequence of having PTSD. High TV viewing levels may be linked with ineffective coping strategies or social isolation, which increase risk of developing PTSD.