Objective: The purpose of this study was to examine the base rates and longitudinal trajectory of individual self-reported postconcussion symptoms from 1-year to 2-years following injury in military service members with and without traumatic brain injury (TBI). Method: Participants were 57 U.S. military service members (Age: M = 31.7, SD = 8.2; 90.7% male) enrolled in a prospective 15-year longitudinal study. Participants included 42 service members who had sustained a mild-moderate TBI and 15 injured controls without TBI (i.e., Trauma Controls [TC]) who had completed the Neurobehavioral Symptom Inventory (NSI) at 1-year (M = 12.7 months, SD = 2.4) and 2-years (M = 23.8 months, SD = 0.5) post-injury. Results: The TBI group reported a significantly higher number of NSI symptoms compared to the TC group at Year 1 (p = .045, d = .67) and Year 2 post-injury (p = .008, d = .88). In the TBI group, the most frequently reported symptoms at Year 1 were difficulty sleeping, headaches, frustration, irritability, poor concentration, numbness/tingling, forgetfulness, and fatigue (40.4-54.7%). Of those who reported these symptoms, a minority continued to report the same symptoms at Year 2 (5.0-17.6%), with the exception of fatigue (31.6%) and forgetfulness (22.2%). In the TC group, the most frequently reported symptoms at Year 1 were numbness/tingling, fatigue, difficulty sleeping, headaches, frustration, and noise sensitivity (26.6-40.0%). A substantial proportion of the TC group continued to report these symptoms at Year 2 (20.1-66.8%). Conclusion: In both the TBI and TC group, while many NSI symptoms were reported at Year 1 post-injury and had resolved at 2-years post-injury, the persistence of some symptoms over time, and the development of “new” symptoms, was common.