Abstract: Objectives: To examine the psychometric properties of an assessment measure for posttraumatic stress disorder (PTSD) that corresponds with the current version of the Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition (DSM-5) in older adults. Design: Cross-sectional study. Setting: Nationally representative web-based survey (National Health and Resilience in Veterans Study; NHRVS) between November 18, 2019 and March 8, 2020. Participants: A total of 3001 veterans aged 60 years and older (mean age=73.2 years) Measurements: PTSD symptoms were assessed using the PTSD Checklist for DSM-5 (PCL-5). Results: PCL-5 scores demonstrated excellent internal consistency, and strong convergent and discriminant validity. Veterans who met criteria for probable PTSD and subthreshold PTSD had higher rates of childhood and adult trauma exposure than those who did not meet criteria for either of these groups. A recently proposed 8-factor model provided the best fit to item-level PCL-5 data, with dysphoric (i.e., anhedonia, dysphoric arousal) symptoms having the strongest most consistent associations with measures of functioning. Conclusions: This is the first known study to examine the psychometric properties of the PCL-5 among older veterans. Results indicate that the PCL-5 is a reliable and valid instrument for use with community-dwelling older veterans. The finding that dysphoric symptoms of PTSD were most consistently linked to measures of functioning underscores the importance of targeting these symptoms as part of prevention, assessment, and treatment efforts in this population.