Objective: This study investigated the effects of a school-based skill-training intervention in attention control and executive functions for pupils with hyperactivity-impulsivity (H-I) and cognitive control (CC) deficits. The main aim was to examine whether the intervention differently influenced H-I and CC, and whether cognitive abilities or conduct problems moderated response to the intervention.

Method: Elementary school pupils from 41 schools participated the study and were divided into an intervention group (n = 71) and a waitlist control group (n = 77). Intervention outcomes were assessed with an inventory assessing executive function difficulties (including H-I and CC) completed by classroom teachers.

Results: Significant intervention effects and positive changes were detected in CC but not in H-I. Significant intervention effects were found mainly among pupils with low levels of conduct problems.

Conclusions: The results suggest that a skill-training intervention has specific positive effects on CC, but conduct problems may diminish response to intervention.