Objective: Our goal was to determine whether behavioral economic constructs--including impulsivity (i.e., steep discounting of delayed food and monetary rewards), the relative reinforcing value of food (RRV[subscript food]), and environmental enrichment (i.e., the presence of alternatives to unhealthy foods in the home and neighborhood environments)--are significant pretreatment predictors of overweight children's weight loss within family-based treatment. Method: Overweight children (N = 241; ages 7-12 years; 63% female; 65% non-Hispanic White) enrolled in a 16-week family-based obesity treatment with at least one parent. At baseline, children completed a task to assess RRV[subscript food] and delay discounting measures of snack foods and money to assess impulsivity. Parents completed questionnaires to assess environmental enrichment. Results: Children who found food highly reinforcing and steeply discounted future food rewards at baseline showed a blunted response to treatment compared with children without this combination of risk factors. High environmental enrichment was associated with treatment success only among children who did not find food highly reinforcing. Monetary discounting rate predicted weight loss, regardless of children's level of RRV[subscript food]. Conclusions: Investigation is warranted into novel approaches to obesity treatment that target underlying impulsivity and RRV[subscript food]. Enriching the environment with alternatives to unhealthy eating may facilitate weight loss, especially for children with low RRV[subscript food]. (Contains 4 tables and 1 figure.)