This study explored the experiences of individuals who self‐identify as providing support to a friend, family member, or significant other with posttraumatic stress disorder (PTSD). We analyzed and coded a total of 345 posts from an online support forum, with reference to 13 categories (finances, life interference, venting/emotional expression, maltreatment, sexual behavior, distress, prevented expression, physical health, communication, no personal space, isolation, and compassion fatigue). Categories for coding were established a priori and based on previous literature about caregiving and supporting. Results suggested that informal PTSD caregivers experience concerns involving interpersonal relations, emotional turmoil, and barriers to care for themselves and the individual they are caring for. This study provides a preliminary examination of the experiences and concerns of PTSD caregivers. Implications and suggestions for future research are discussed.