The aim of the study was to analyze the influence of socioeconomic status (SES) and age on school-age children’s performance in language, attention, and memory tasks and to examine the socioeconomic variables that predict their execution. An intentional sample of 228 rgentinean children aged 8-11 years from two SES (low and medium) was used. Multivariate analysis of variance and hierarchical regression analysis were employed. Results revealed a significant effect of SES and age on the cognitive functions studied. Based on the socioeconomic variables analyzed, maternal instruction level (MIL) was found to be the main predictor of the child’s cognitive performance. In addition, MIL explained a percentage of variance in the child’s performance, even after controlling for the child’s age and receptive language level. Results are discussed in terms of the influence of SES on cognitive performance and the possible predicting and mediating factors of this association.The aim of the study was to analyze the influence of socioeconomic status (SES) and age on school-age children’s performance in language, attention, and memory tasks and to examine the socioeconomic variables that predict their execution. An intentional sample of 228 Argentinean children aged 8-11 years from two SES (low and medium) was used. Multivariate analysis of variance and hierarchical regression analysis were employed. Results revealed a significant effect of SES and age on the cognitive functions studied. Based on the socioeconomic variables analyzed, maternal instruction level (MIL) was found to be the main predictor of the child’s cognitive performance. In addition, MIL explained a percentage of variance in the child’s performance, even after controlling for the child’s age and receptive language level. Results are discussed in terms of the influence of SES on cognitive performance and the possible predicting and mediating factors of this association.