Our study did not reveal any relationships between prenatal (or postnatal) maternal depression with frontal EEG activity nor frontal connectivity of infants at 6 months and 18 months of age. Interestingly, however, an increase in depressive symptoms from the prenatal to postnatal time period predicted greater right frontal activity and relative right frontal asymmetry at 6 months of age, and subsequently lower right frontal connectivity at 18 months of age, which in turn predicted children’s externalizing behavior at 24 months of age.