Rates of childhood obesity and parental incarceration have been increasing in the United States since the 1970s. We examined whether parental incarceration was associated with child overweight at age 9 and whether that association differed by which parent was incarcerated.We ran cross-sectional logistic regression models predicting the likelihood of a child being overweight, conditional on whether the child's mother, father, or both parents had ever been incarcerated. Our sample included non-Hispanic black (n = 1638) and non-Hispanic white (n = 504) children who were surveyed at age 9 in the Fragile Families and Child Wellbeing Study, a stratified random sample of new and mostly unmarried parents in US cities with populations >200 000. Children were born between 1998 and 2000.Controlling for race, sex, parental socioeconomic status, maternal obesity, parental impulsivity, and child temperament, the odds of being overweight were significantly lower if a child's mother was the only parent ever incarcerated (adjusted odds ratio [aOR] = 0.43; 95% confidence interval [CI], 0.22-0.83) or if both parents were ever incarcerated (aOR = 0.58; 95% CI, 0.38-0.87) compared with children whose parents were never incarcerated. Having a father who had ever been incarcerated had a comparatively meager and nonsignificant effect on the odds of a child being overweight (aOR = 0.81; 95% CI, 0.64-1.01).Our findings contribute to an emerging body of research suggesting that the consequences of parental incarceration for young children's physical health may differ by whether a child's mother or father has ever been incarcerated. Caution is warranted in generalizing the negative behavioral and mental health effects of parental incarceration to child physical health conditions, particularly for young children whose mothers have a history of incarceration.