Trauma exposure and post-traumatic stress disorder (PTSD) are associated with self-reported asthma and chronic obstructive pulmonary disease. However, these conditions have not yet been related to objective measures of lung function. 1,772 adults from the general population were assessed regarding their medical histories and spirometric lung function. Additionally, they were administered a PTSD interview, and assigned to three groups: no trauma; trauma, but no PTSD; and trauma with PTSD. Adjusting for sociodemographic, clinical and lifestyle factors, subjects with PTSD had significantly higher odds ratios for most asthma-related symptoms than PTSD-negative participants (OR 3.2-8.8). The mean ratio of forced expiratory volume in 1 s (FEV₁) to forced vital capacity (FVC) was lowest in the PTSD group and highest in those without trauma exposure. Traumatic stress was independently associated with FEV₁ and FEV₁/FVC. Participants with PTSD, compared with those without, had a significantly increased risk for airflow limitation independent of its definition (OR 4.2-7.8). This is the first study relating traumatic stress and PTSD, respectively, to objective parameters of lung function. Our findings suggest an association of trauma exposure and PTSD with airflow limitation, which may be mediated by inflammatory processes.