To describe school performance in pediatric intensive care survivors, as well as the influence of chronic diseases, psychological well-being, and family socioeconomic status on poor school performance. Register-based observational descriptive follow-up study. A multicenter national study. All pediatric patients who were admitted to an ICU in Finland in 2009-2010. Children and adolescents of or beyond school age. None. Questionnaires regarding the child's coping in school classes, chronic illnesses, as well as family socioeconomic factors were sent to every child alive 6 years after discharge from intensive care in Finland. Mental well-being was measured with the Strengths and Difficulties Questionnaire. There were 1,109 responders in an ICU group of 3,674 children. Seven-hundred fifty-three of the respondents were of school age or older. Of these, 13% (101/753) demonstrated poor school performance. Children with difficulties in school more often had a need for regular medication (71.3% vs 32.4%; p < 0.001), healthcare visits (91.1% vs 80.6%; p = 0.01), some regular therapy (60.4% vs 13.7%; p < 0.001), chronic illnesses (86.3% vs 48.4%; p < 0.001), or additional ICU admissions (36.5% vs 14.9%; p = 0.003). Schooling difficulties were reported more often in children with abnormal Strengths and Difficulties Questionnaire scores compared to those with normal or borderline scores (24.8% vs 5.4%; p < 0.001). In an adjusted logistic regression model, which included age, number of chronic diseases, and need for therapy, poor school performance was predicted by abnormal Strengths and Difficulties Questionnaire scores, nonacademic parental education, and paternal manual labor status. Difficulties in school were more frequent when the child had chronic comorbid illnesses, especially neurologic or chromosomal abnormalities, had poor mental health, father was employed in manual labor, or parents were uneducated.