Number sense and self-regulation are considered foundational skills for later school learning. This study aimed to investigate the predictive power of kindergarten children's number sense and self-regulation scores on their mathematics and Turkish language examination scores in the 5th and 6th grades. The participants in this study were 5th grade (n = 46) and 6th grade (n = 28) students, whose number sense and self-regulation skills were measured when they were in kindergarten in 2009 and 2010. Data were analyzed through multiple regression. The results showed positive and mid-level correlations. The children's kindergarten number sense and self-regulation scores significantly predicted their 5th and 6th grade mathematics and Turkish language examination scores. Self-regulation was the stronger predictor of mathematics scores, whereas number sense scores were the better predictor of Turkish language examination scores. The findings from this study provide further evidence as to the critical role of children's early skills in middle school mathematics and language achievement.