Epidemiological evidence suggests that exposure to adverse childhood experiences (ACEs) is associated with sexual risk, especially during adolescence, and with maternal and child health outcomes for women of reproductive age. However, no work has examined how ACE exposure relates to sexual risk for women during the postpartum period. In a convenience sample of 460 postpartum women, we used linear and logistic regression to investigate associations between ACE exposure (measured using the Adverse Childhood Experiences Scale) and five sexual risk outcomes of importance to maternal health: contraceptive use, efficacy of contraceptive method elected, condom use, rapid repeat pregnancy, and incidence of sexually transmitted infections (STIs). On average, women in the sample were 25.55 years of age (standard deviation = 5.56); most identified as Black (60.4%), White (18%), or Latina (14.8%). Approximately 40% were exposed to adversity prior to age 18, with the modal number of experiences among those exposed as 1. Women exposed to ACEs were significantly less likely to use contraception; more likely to elect less-efficacious contraceptive methods; and used condoms less frequently (p = 0.041 to 0.008). ACE exposure was not associated with rapid repeat pregnancy or STI acquisition, p > 0.10. Screening for ACEs during pregnancy may be informative to target interventions to reduce risky sexual behavior during the postpartum period.