Poor sleep quality among individuals with posttraumatic stress disorder (PTSD) is associated with poorer prognosis and outcomes. The factor structure of the most commonly employed measure of self-reported sleep quality, the Pittsburgh Sleep Quality Index (PSQI), has yet to be evaluated among individuals with PTSD. The current study sought to fill this gap among a sample of 226 U.S. military veterans with PTSD (90% with co-occurring mood disorders, 73.5% with substance use disorders). We evaluated the factor structure of the PSQI by conducting an exploratory factor analysis (EFA) in approximately half of the sample (n = 111). We then conducted a second EFA in the other split half (n = 115). Lastly, we conducted a path analysis to investigate the relations between sleep factors and PTSD symptom severity, after accounting for the relation with depression. Results suggested sleep quality can best be conceptualized, among those with PTSD, as a multidimensional construct consisting of 2 factors, Perceived Sleep Quality and Efficiency/Duration. After accounting for the association between both factors and depression, only the Perceived Sleep Quality factor was associated with PTSD (β = .51). The results provide a recommended structure that improves precision in measuring sleep quality among veterans with PTSD.