IMPORTANCE The prevalence of weight-related problems in adolescents is high. Parents of adolescents may wonder whether talking about eating habits and weight is useful or detrimental. OBJECTIVE To examine the associations between parent conversations about healthful eating and weight and adolescent disordered eating behaviors. DESIGN Cross-sectional analysis using data from 2 linked multilevel population-based studies. SETTING Anthropometric assessments and surveys completed at school by adolescents and surveys completed at home by parents in 2009-2010. PARTICIPANTS Socioeconomically and racially/ethnically diverse sample (81% ethnic minority; 60% low income) of adolescents from Eating and Activity in Teens 2010 (EAT 2010) (n = 2793; mean age, 14.4 years) and parents from Project Families and Eating and Activity in Teens (Project F-EAT) (n = 3709; mean age, 42.3 years). EXPOSURE Parent conversations about healthful eating and weight/size. MAIN OUTCOMES AND MEASURES Adolescent dieting, unhealthyweight-control behaviors, and binge eating. RESULTS Mothers and fathers who engaged in weight-related conversations had adolescents who were more likely to diet, use unhealthy weight-control behaviors, and engage in binge eating. Overweight or obese adolescents whose mothers engaged in conversations that were focused only on healthful eating behaviors were less likely to diet and use unhealthy weight-control behaviors. Additionally, subanalyses with adolescents with data from 2 parents showed that when both parents engaged in healthful eating conversations, their overweight or obese adolescent children were less likely to diet and use unhealthy weight-control behaviors. CONCLUSIONS AND RELEVANCE Parent conversations focused on weight/size are associated with increased risk for adolescent disordered eating behaviors, whereas conversations focused on healthful eating are protective against disordered eating behaviors.