Brain fog is one symptom that has been underexplored in traumatic brain injury (TBI). We explored the cognitive and affective correlates of brain fog in people with symptomatic mild TBI (n = 15), moderate-to-severe TBI (n = 15), and a healthy control group (n = 16). Measures across the studies assessed “brain fog” (Mental Clutter Scale), objective cognition (Useful Field of View® and Cogstate Brief Battery®), post-concussive symptoms (Post-Concussion Symptom Scale), and depressive symptoms (Profile of Moods Scale). Brain fog was higher in symptomatic mild TBI and moderate-to-severe TBI compared with healthy controls. Greater brain fog corresponded to greater depressive symptoms in symptomatic mild TBI. Greater brain fog corresponded to poorer episodic memory and working memory in moderate-to-severe TBI. Brain fog appears to reflect challenges in recovery, including depressive symptoms and worse cognitive function. Screening for brain fog might be worthwhile in people with brain injuries.