The high prevalence of obesity among children, coupled with the strong link between child weight and parent weight, highlights the importance of identifying successful interventions that use parents as the agent of change to encourage sustainable healthy behaviors in children. The purpose of this dissertation was to identify successful intervention strategies for intervening with parents of young children. Aim One used a serial mediation model to evaluate the mediating effect of exercise barriers and moderate-to-vigorous physical activity (MVPA) changes on the relationship between number of children in the home and weight change of adults (N=263) in an 18-month behavioral weight loss intervention. An increasing number of children in the home was associated with lower percent weight loss at 6 months, which was mediated by greater exercise barriers at baseline and a lower increase in MVPA by 6 months. There was no relationship between number of children in the home and percent weight regain from 6 to 18 months. Aim Two was a 6-month randomized controlled trial that tested the efficacy of an intervention that targeted mothers of children ages 3 to 5 (N=51) to reduce child sugar-sweetened beverage (SSB) consumption and maternal weight through the use of a smartphone-delivered website, text messages, and simplified self-monitoring compared to a waitlist control group. Children in Smart Moms reduced their SSB intake significantly more than children in the control group at 6 months (-9.5 oz. vs. -1.9 oz., p