Previous studies examining the relationship between emotion dysregulation and externalizing behavior problems have, so far, focused on using general screening questionnaires capturing a wide range of externalizing behaviors and emotion dysregulation has mostly been assessed through direct observation using negative mood induction and behavioral tasks. The purpose of this study was to explore this relationship using a multi-informant rated clinical questionnaires. Parents and teachers of 609 5–6-year-old children (46% girls, 54% boys) completed the ERC, DBRS, and SDQ. ODD symptoms/conduct problems and lability/negativity were more severe among boys but girls had better emotion regulation. The results also showed a significant main effect for emotion dysregulation and ODD symptoms/conduct problems and that gender had no moderating effect on the relationship. These findings show a strong association between emotion dysregulation and concurrent ODD symptoms/conduct problems and suggest that emotional difficulties should be considered when exploring causes of behavior difficulties in daily life.