Maternal risk drinking may be a risk factor for child behavior problems even if the mother has discontinued this behavior. Whether pre-pregnancy risk drinking is an independent predictor of child behavior problems, or whether a potential effect may be explained by maternal alcohol use during and after pregnancy or other adverse maternal characteristics, is not known. Employing data from the Norwegian Mother and Child Cohort Study (MoBa), longitudinal associations between maternal pre-pregnancy risk drinking and behavior problems in toddlers aged 18 and 36 months were examined. Included in the study was mothers answering MoBa questionnaires when the child was 18 (N = 56,682) and 36 months (N = 46,756), and who had responded to questions regarding pre-pregnancy risk drinking at gestation week 17/18, using the screening instrument T-ACE. Toddler behavior problems were measured with items from Child Behavior Checklist. Associations were analyzed with multivariate logistic regression, controlling for pre and postnatal alcohol use, as well as other relevant covariates. Pre-pregnancy risk drinking was associated with child behavior problems at 18 and 36 months, even after controlling for pre and postnatal alcohol use. Maternal ADHD and anxiety and depression were the only covariates that had any substantial impact on the associations. When all covariates were included in the model, the associations were weak for internalizing behavior problems and non-significant for externalizing behavior problems. Pre-pregnancy risk drinking may predict early development of behavior problems in the offspring. This increased risk may be due to other adverse maternal characteristics associated with risk drinking, in particular co-occurring maternal psychopathology.