Purpose: This study was designed to assess the efficiency of a French version of "GraphoGame" (GG) against an equally engaging math intervention ("Fiete Math," FM) in a large school sample of children from socioeconomically disadvantaged neighborhoods in grade 1 (N = 921). Method: The intervention was implemented in two different cohorts who used GG or FM for about four months four times a week for 30 minutes. Gains in reading and mathematics were assessed before and after intervention. Given the nested nature of the data, results were analyzed using hierarchical linear mixed effect models with intervention and initial pretest level as fixed effects and individuals and classes as random effects. Results: We found positive intervention effects of GG on phoneme awareness (effect size, ES = 0.23), orthographic choice (ES = 0.27) and word reading fluency (ES = 0.18). FM had a significant effect on math achievement (ES = 0.28) but not number comparison. Correlations between intervention gains and game variables (overall accuracy, number of levels played) suggest that the effects of GG were specific. Conclusions: Positive effects for focused digital reading and math interventions were found in a large school sample of children from socially disadvantaged neighborhoods.