Exposure to traffic noise has been associated with adverse effects on neuropsychological development in children, but the results with regard to behavioral problems are inconsistent. In this study, we investigated associations between residential road traffic noise exposure and behavioral problems in 7-year old children using data from a national birth cohort in which we identified 46,940 children with complete information on both behavioral problems at 7 years of age and address history from conception to 7 years of age. Road traffic noise (L_den) was modeled at all present and historical addresses and behavioral problems were assessed by the Strengths and Difficulties Questionnaire. Associations between pregnancy and childhood exposure to noise and behavioral problems were analyzed by multinomial logistic regression models and adjusted for potential confounders. We found that for mean time-weighted exposure from birth to 7 years of age, a 10 dB higher road traffic noise was associated with a 7 % higher risk for scoring abnormal (95% CI: 1.00-1.14) compared to normal scores on the total difficulties score. A 5 % higher risk for scoring borderline (95% CI: 1.00-1.10) and a 10 % higher risk for scoring abnormal (95% CI: 1.03-1.18) were found on the hyperactivity/inattention subscale. Exposure to road traffic noise during the pregnancy period was not associated with child behavioral problems at 7 years of age. In conclusion, this study indicates that residential road traffic noise in early childhood may increase the risk for behavioral problems, particularly hyperactivity/inattention symptoms.