Background: Structured out-of-school time (OST) activities are associated with positive academic and psychosocial outcomes. Methods: Data came from the 2007 National Survey of Children's Health, restricted to 36,132 youth aged 12-17 years. Logistic regression models were used to examine the joint effects of race/ethnicity and immigrant family type on the participation in OST activities. Results: Compared with US-born (USB) non-Hispanic White youth with USB parents, USB Hispanic youth with USB parents were less likely to participate in sports, whereas non-Hispanic Black youth with immigrant parents were more likely to participate in sports. White youth with at least 1 immigrant parent had higher odds of participating in after-school clubs. All Hispanic youth were less likely to participate in after-school clubs. USB Hispanic youth, USB Black youth, and White youth and "other" youth with at least 1 immigrant parent had higher odds of engaging in community services. Youth from immigrant families had lower odds of doing paid work. Conclusions: Hispanic youth were less likely to participate in OST activities. Non-Hispanic youth with immigrant parents did not engage in fewer OST activities compared with USB White youth with USB parents. Intervention and recruitment strategies for OST activities may need to be customized for immigrant groups. (author abstract)