Children prenatally exposed to opioids exhibit impairments in cognitive functioning and have an increased likelihood of experiencing other forms of adversity. Given that these other forms of early life adversity are linked to lower levels of cognitive functioning, it is important to determine whether the association between opioid exposure and cognitive functioning is better explained by other forms of adversity. The current study used a practical design (i.e., caregiver report of a preschool-aged child's exposure to opioids during gestation) to examine the associations between prenatal opioid exposure status (i.e., presence or absence of exposure), postnatal adversity, and preschool-age cognitive functioning. Forty-four preschool-age children, 21 with prenatal opioid exposure (20 of whom were adopted) and 23 comparison children, and their caregivers were invited to a laboratory session during which the child completed a neuropsychological assessment battery while caregivers were interviewed about their child and completed questionnaires. Regression analysis was conducted to examine whether prenatal opioid exposure status explained variation in cognitive functioning over and above child adversity. Children with prenatal opioid exposure had lower full-scale IQ scores than comparison children (Cohen's d =-0.86). After accounting for exposure to postnatal adversity, prenatal opioid exposure status explained 6.01% of the variance in full-scale IQ scores. Taken together, our results suggest that the association between prenatal opioid exposure status and cognitive functioning at preschool age is not better explained by postnatal adversity. These findings underscore efforts to reduce opioid use among people who are pregnant or likely to become pregnant.