Self-regulation abilities are known to be a central determinant of educational success and a wide range of other important life outcomes. We conducted a randomized-controlled trial with about 600 first graders to identify the causal effect of a targeted self-regulation training on self-regulation abilities, concentration, and educational outcomes. Results demonstrate that our self-regulation training increases long-term outcomes 12 months after treatment for attention and inhibition abilities, self-regulation behavior, as well as reading abilities. There is no treatment effect on math abilities, fluid IQ, and on one of our concentration tasks. We conclude that targeted training of self-control abilities in early years can substantially improve these self-regulation abilities in the long run, that these improvements potentially serve as a multiplier for the promotion of schooling abilities, and thus that this kind of training might be an effective tool to foster the skill formation process.