To determine the prevalence of head injuries (HIs), posttraumatic stress disorder (PTSD), and depressive symptoms in law enforcement officers (LEOs) and (2) the association between HIs and psychological health conditions. County-level survey administered via Research Electronic Data Capture. A total of 381 LEOs completed the survey (age=43±11years; 40 [11%] females; time as LEO=1-50years, median=15years). Cross-sectional study. We examined the prevalence of HIs (the Ohio State University Traumatic Brain Injury Identification Method), PTSD (PTSD Checklist-Civilian [PCL-C]), and depressive symptoms (Patient Health Questionnaire-9 [PHQ-9]). We used Mann-Whitney U and chi-square analyses to compare PTSD and depressive symptoms between those with and without a HI history. There were 282 (74%) participants who reported a lifetime history of 1 or more HIs; 116 (30%) sustained 1 or more HIs on the job. PCL-C scores ranged 17 to 85 (median=27); 33 (10%) participants met or exceeded the clinical cutoff score of 50 to indicate a positive PTSD screening. Participants with a HI history (median=29) had higher PCL-C scores than those with no HI history (median=24; P <.001), but the proportion of participants who met the clinical cutoff for PTSD was not different between those with (n =28, 11%) and without (n =5, 5%) a HI history (X2=2.52, P =.112, odds ratio=2.18; 95% confidence interval, 0.82-5.83). PHQ-9 scores ranged 0 to 20 (median=3); 124 (36%) participants reported mild or greater depressive symptoms. Participants with a HI history (median=3) had higher depressive symptoms than those with no HI history (median=2; P =.012). The proportion of participants with mild or greater depressive symptoms was higher among those with a HI history (n =99, 39%) than without (n =25, 27%; X2=4.34, odds ratio=1.74; 95% confidence interval, 1.03-2.93). HIs are prevalent in LEOs, which may have consequences for their performance, well-being, and career longevity. PTSD and depressive symptoms are higher in those with a HI history, suggesting LEOs need better traumatic brain injuries and mental health resources.