This study explores the relationship of early immersion education, socioeconomic background, and cognitive gains of young learners. We examine the possible advantages of early bilingual education and the impact of family socioeconomic status (SES) for the cognitive development of children. Participants (N = 39) were students at regular (German) or immersion (German-English) primary schools in Germany. The study employed a longitudinal design with school program and socioeconomic status as between-subjects factors, and L2 proficiency and cognitive variables as within-subject factors. The pre- and post-tests consisted of tests of English vocabulary and grammar and tests of working memory capacity, non-verbal intelligence, and phonological awareness. Participants also completed a parental questionnaire assessing their socioeconomic background based on HISEI indicators (Highest International Socioeconomic Index). Repeated measures ANOVAs and regression analyzes revealed that the participants from the immersion school outperformed their peers from the regular schools on all L2 (English) proficiency and cognitive variables on the posttest. Furthermore, our data revealed that SES is significantly more influential in participants who follow regular school programs than in those who are enrolled in immersion schools. Overall, our data provide support for the benefits of early immersion programs in leveling the playing field for children of low socioeconomic status.