Abstract Objective This study aims to lend additional empirical support for the relationship between cognitive proficiency and trauma. Importantly, the study seeks to advance our understanding of this relationship by investigating the possible moderating role of cognitive flexibility (CF). It was hypothesized that the relationship between trauma and cognitive proficiency would be stronger for individuals with less CF. Method Data were collected from 75 adult participants in a private practice. The sample was predominantly White and female, and all consented to a comprehensive neuropsychological assessment following referral for inattention and personal trauma. Relevant measures included the focused anxiety-trauma subscale of the Personality Assessment Inventory, the Cognitive Processing Index of the Weschler Adult Intelligence Scale, and Trails B to determine the correlation between trauma symptoms and cognitive proficiency and to evaluate whether CF moderated the relationship. Results Results indicated that greater trauma symptoms were associated with lower cognitive proficiency (B = −0.448, SE = 0.090, β = −0.554, p < 0.001). The interaction between trauma symptoms and CF was also significant (B = 0.007, SE = 0.002, β = 0.506, p < 0.001), suggesting the effect of trauma on cognitive proficiency depended upon the level of CF. Together, the variables accounted for approximately 30% of the variance in cognitive proficiency (R2 = 0.299, F(2, 73) = 15.574, p < 0.001). Conclusion This study supports the hypothesis that the impact of psychological trauma on cerebral efficiency is partially dependent on CF. These findings spotlight CF as a potential target for intervention to mitigate the cognitive effects of trauma.