The present study set out to evaluate the effectiveness of a group cognitive intervention aimed at promoting executive functions in children at social risk, and its resulting effect on school performance. The quasi-experimental, pretest-posttest design included a control group. The sample was made up of 178 children (52% boys), aged 6-10. The children were evaluated by means of a battery of neuropsychological EF tests, learning achievement tests, and a teacher-rated behavioral EF scale. The intervention program included 30 group cognitive stimulation sessions that increased in difficulty and was embedded into school curricula. Trained children performed better in terms of cognitive flexibility, planning, metacognition, inhibitory control, word identification and dictation, as compared to their baseline values and children in the control group. This study provides new evidence of the effectiveness of cognitive interventions in children and its possibility to transfer cognitive gains to school performance contexts.Key words: cognitive intervention, executive functions, school performance, children, poverty.