Communication deficits are frequently associated with externalizing behavior problems in preschoolers but, in most cases, unsuspected in clinical practice. This exploratory study evaluated the effectiveness of a relatively brief parent-implemented language intervention on preschoolers at risk for behavior problems. Participants were randomly allocated either to an experimental group (n = 16) or to an untreated control group (n = 16). An intervention of eight group sessions, aiming at enhancing parent verbal responsiveness and communication strategies, was implemented over 2 months. Results showed that this intervention created several improvements such as an enhancement of parental responsiveness and a trend toward increased child referential communication abilities and decreased child behavior problems. These effects persisted 6 months after the intervention. Despite some limitations and the need for a replication of these results, the findings highlight the importance of preventive interventions on parent-child communication and interactions in supporting the communication needs of children with externalizing behavior difficulties.