Using data from a U.S. national sample of 1644 parent-teen dyads from the National Cancer Institute’s Family Life, Activity, Sun, Health, and Eating study, we show that parents’ and teens’ beliefs and intentions for limiting screen time sedentary behavior (SD) and junk food/sugary drink consumption (JF) not only influence their own behaviors (actor effects), but also each other’s intentions and behaviors (partner effects). Participants reported SD and JF as well as indicators of their attitudes, subjective norms, perceived behavioral control (PBC), and intentions for each behavior. There were significant actor effects from beliefs (attitudes, norms, PBC) to intentions (β=0.049-0.601) and to behavior (β=-0.160-0.156) for both behaviors and from intentions to behavior for JF. There are also significant partner effects for both behaviors. Parents’ beliefs predict both teen intentions (β=-0.053-0.067) and behaviors (β=-0.006-0.051), and teen beliefs predict both parents’ intentions (β=0.047) and behaviors (β=-0.057-0.119). This research places the Theory of Planned Behavior in a dyadic frame, highlighting how the beliefs of close others influence individuals’ health behaviors.