Executive Functions (EFs) describe a set of cognitive control abilities that help children to develop self-regulated behavior and do well in their schooling. The promotion of EFs in children at social risk is an area of relevance for neurosciences and education. On this basis, the present study set out to analyze a school-based intervention targeted to strengthening EFs in Argentine children at social risk. Participants were 69 children from 8 to 10 years old, from an urban-marginalized federal school in Mendoza. A quasi-experimental pre-test post-test design was used, with a control group. The cognitive intervention was embedded in the school curriculum and was carried out for a month and a half. The schoolchildren were evaluated before and after the intervention with EFs’ neuropsychological tests. The main results showed that the group cognitive intervention was associated with gains in the schoolchildren’s attention processes, although it did not favor other EFs, which could indicate moderate effectiveness. These data provide evidence in favor of ecological interventions as a way to promote attention development trajectories in children at social risk, and in turn, draw up guidelines to reflect on the design and the modalities of school-based interventions.