The prevalence of obesity among women of childbearing age has been rising dramatically over the last decades. Pre-pregnancy obesity may have negative neurodevelopmental consequences for the offspring. The present study examined the association of maternal pre-pregnancy overweight and obesity with child behavior problems and executive functioning at age 5 years. Data of 4094 mother-child pairs of the Amsterdam Born Children and their Development birth cohort study was used. Child behavioral problems were assessed with the maternal and teacher version of the Strengths and Difficulties Questionnaire. Two executive functioning constructs, inhibitory control and cognitive flexibility, were measured with the Response Organization Objects task of the Amsterdam Neuropsychological Tasks test battery. Increased maternal pre-pregnancy BMI was associated with an increase in children's behavioral problems (OR total behavioral problems reported by mothers pre-pregnancy obesity versus normal weight: 1.78 [95% CI 1.17 to 2.69] and reported by teachers for pre-pregnancy overweight versus normal weight: 1.32 [1.00 to 1.74]). Maternal pre-pregnancy obesity was associated with an increase in peer relationship problems reported by teachers (OR: 1.77 [1.18 to 2.64]). It was also associated with a small decrease in cognitive flexibility (increased Reaction Time in ms: B = 67.59 [5.88 to 129.30] and Within Subject Standard Deviation in ms: B = 76.46 [32.00 to 120.92]), but not with inhibitory control. Cognitive flexibility did not mediate the association between maternal pre-pregnancy BMI and children's behavioral problems.