This study examined the association between medically attended traumatic brain injury (TBI) and in-prison behavioral infractions in a statewide population by comparing rate ratios of infractions in inmates with and without TBI over an 11.5-year period (16,299 males and 1,270 females). The in-prison behavioral infraction rate was significantly increased in males with TBI compared with no TBI for all infractions (RR = 1.32, 95% CI: 1.12, 1.55), violent infractions (RR = 1.86, 95% CI: 1.54, 2.24), and nonviolent infractions (RR = 1.19, 95% CI: 1.00, 1.41). The violent behavioral infraction rate was significantly increased in females with TBI compared with no TBI (RR = 2.44, 95% CI: 1.45, 4.12). A clearer understanding of inmates with a history of TBI and further examination of the association of TBI and behavioral infractions are needed.