BACKGROUND: Polybrominated diphenyl ethers (PBDEs), synthetic chemicals previously used as flame retardants in commercial products, impact human behaviors, mood symptoms and cognitive abilities. OBJECTIVE: We estimated the association of gestational PBDE serum concentrations with early adolescent self- and caregiver-reported ratings of executive function in a prospective pregnancy and birth cohort. METHODS: We measured gestational serum concentrations of five PBDE congeners and created a summary exposure variable (∑ RESULTS: As higher scores indicate greater deficits in executive function, gestational PBDE concentrations were positively associated with adolescent-reported BRIEF-2 T-scores for Global Executive Composite (BDE-28: β = 6.31 (95%CI: 2.59, 10.03), BDE-47: (β = 3.32 (95%CI: 0.1, 6.54), ∑ DISCUSSION: This study provides evidence that gestational PBDE serum concentrations may adversely influence offspring executive function during adolescence.