The aims were to investigate mental health problems with the Strength and Difficulties Questionnaire (SDQ) in children born extremely preterm/extremely low birth weight (EP/ELBW) without severe disabilities compared to controls, and to identify peri-, or neonatal factors possibly predicting later mental health problems. A national Norwegian cohort of 11-year-old EP/ELBW children, excluding those with intellectual disabilities, non-ambulatory cerebral palsy, blindness and/or deafness, was assessed. Parents and teachers completed the SDQ. Mean scores and scores ≥90th percentile for the control group, combined (parent and/or teacher reporting the child ≥90th percentile), and pervasive ratings (both parent and teacher reporting the child ≥90th percentile) were presented. The controls consisted of an unselected population of all 11-year-old children born in 1995 who attended public or private schools in Bergen. Of the eligible children, 216 (64%) EP/ELBW and 1882 (61%) control children participated. The EP/ELBW children had significantly higher scores and/or increased risk of parent, teacher, combined, and pervasive rated hyperactivity/inattention, emotional-, and peer problems (OR 2.1-6.3). Only parents reported the EP/ELBW children to be at an increased risk of conduct problems (OR 1.6, 95% CI 1.1-2.6). Only low maternal education at birth was significantly associated with mental health problems at 11 years of age (OR 2.5, 95% CI 1.2-5.4). EP/ELBW children without severe disabilities had increased risk of symptoms of hyperactivity/inattention, emotional-, and peer problems. None of the peri- or neonatal factors were significantly associated with later mental health problems, except for low maternal education.