Background: Little is known about the stability of obsessive-compulsive (OC) behavior during childhood. The objective of this study is to determine the developmental stability of pediatric OC behavior and the genetic and environmental influences on stability in a large population-based twin sample. Methods: Maternal and paternal ratings on the 8-item Obsessive Compulsive Scale of the Child Behavior Checklist (CBCL-OCS) on Dutch mono- and dizygotic twin pairs from 8083 families were collected at ages 7, 10, and 12 years. Using a longitudinal twin design, stability of OC behavior and genetic and environmental influences on stability were determined. Using cutoff criteria, persistent, resilient, and new onset cases were identified in this sample. Results: OC behavior assessed by the CBCL-OCS showed a moderate stability with phenotypic correlations of around .50 for boys and for girls. Stability of OC behavior was influenced by genetic factors, by environmental factors shared by children growing up in the same family, and by non-shared environmental factors. Stability for OCS was lower when categorical data were analyzed than when quantitative definitions were used. Conclusions: OC behavior is moderately stable in childhood. Stability of OC behavior is influenced by genetic, shared, and non-shared environmental factors.