ObjectiveDetermine anxiety trajectories and predictors up to 10 years posttraumatic brain injury (TBI). DesignProspective longitudinal, observational study. SettingInpatient rehabilitation centers. Participants2836 participants with moderate to severe TBI enrolled in the TBI Model Systems National Database who had ≥2 anxiety data collection points (N=2836). Main Outcome MeasureGeneralized Anxiety Disorder-7 (GAD-7) at 1, 2, 5, and 10-year follow-ups. ResultsLinear mixed models showed higher GAD-7 scores were associated with Black race (P<.001), public insurance (P<.001), pre-injury mental health treatment (P<.001), 2 additional TBIs with loss of consciousness (P=.003), violent injury (P=.047), and more years post-TBI (P=.023). An interaction between follow-up year and age was also related to GAD-7 scores (P=.006). A latent class mixed model identified 3 anxiety trajectories: low-stable (n=2195), high-increasing (n=289), and high-decreasing (n=352). The high-increasing and high-decreasing groups had mild or higher GAD-7 scores up to 10 years. Compared to the low-stable group, the high-decreasing group was more likely to be Black (OR=2.25), have public insurance (OR=2.13), have had pre-injury mental health treatment (OR=1.77), and have had 2 prior TBIs (OR=3.16). ConclusionsA substantial minority of participants had anxiety symptoms that either increased (10%) or decreased (13%) over 10 years but never decreased below mild anxiety. Risk factors of anxiety included indicators of socioeconomic disadvantage (public insurance) and racial inequities (Black race) as well as having had pre-injury mental health treatment and 2 prior TBIs. Awareness of these risk factors may lead to identifying and proactively referring susceptible individuals to mental health services.