Background: Many parents use physical forms of punishment, including spanking to correct perceived misbehavior. While some authors suggest spanking/slapping is a distinct and “milder” form of physical punishment, parents’ use of spanking is consistently associated with poor outcomes for their children. However, less is known about the relationship between spanking/slapping and health and behavioral outcomes in adolescence independent of other childhood adversities. Objectives: The objectives of this study were to examine the associations between lifetime experiences of spanking on the bottom and/or slapping on the hand and 3 adolescent outcomes: (a) mental health disorders, (b) physical health conditions, and (c) defiant behaviors, after adjusting for other types of childhood adversities and child maltreatment. Methods: Cross-sectional data from the provincially representative 2014 Ontario Child Health Study ( N = 6,537 dwellings, response rate = 50.8%) were used. The current study focused on one selected child aged 14 to 17 years within a household ( n = 1,883) with data collected from the adolescent and the parent/caregiver. Logistic regression models were used to identify associations with lifetime experiences of spanking/slapping 3 or more times (vs. 0 to 2 times). Results: Lifetime spanking/slapping was independently associated with increased odds of mental health disorders, physical health conditions, and defiant behaviors in adolescence after adjusting for childhood adversities and child maltreatment (unadjusted and adjusted odds ratios ranging from 1.29 to 2.19). Conclusions: These findings suggest that lifetime spanking/slapping is uniquely associated with harmful mental, physical, and behavioral outcomes in adolescence, and efforts should focus on its prevention.