There is scattered but significant psychological and neuropsychological evidence to suggest that mild traumatic brain injury (mild TBI) plays a notable role in the emergence and expression of anxiety. Conversely, there is also empirical evidence to indicate that anxiety may exert a pronounced impact on the prognosis and course of recovery of an individual who has sustained a mild TBI. Although the relationship between mild TBI and anxiety remains unclear, the present body of research attempts to elucidate a number of aspects regarding this topic. Overall, the mild TBI research is rife with inconsistencies concerning prevalence rates, the magnitude and implications of this issue and, in the case of PTSD, even whether certain diagnoses can exist at all. This review obviates the need for greater consistencies across studies, especially between varying disciplines, and calls for a shift from studies overly focused on categorical classification to those concerned with dimensional conceptualization.