The benefits of early childhood education (ECE) to children extend throughout their lives. A more equitable education system is also dependent upon the universalization of ECE, beyond its personal benefits. A limited number of studies have examined the relationship between ECE attendance and educational outcomes in Türkiye, despite its importance at both the educational and systemic levels. As part of this comparative study, we examined the relationship between ECE attendance and academic achievement in Türkiye over the medium and long term. We considered high stakes assessments for the transition to upper-secondary education (at the end of the eighth grade) and higher education (at the end of the 12th grade) within the scope of this study. Based on the official student recordings in Türkiye, ~5.6 million students were analyzed in the study. For the comparison of group means, partial-eta squares were used, and descriptive comparisons were made for the comparison of group rates. There was a stronger relationship between ECE attendance and medium-term achievement. As a result, students who attended an ECE program had significantly higher scores on the transition to upper-secondary education. Despite similar rates of transition, attendance had a higher rate of transition to formal bachelor programs, prestigious higher education programs, and students’ prioritized programs. ECE programs are particularly beneficial to students with low socio-economic status (SES) according to additional analyses. Medium- and long-term academic indicators are correlated with ECE attendance, with the medium-term relationship being particularly robust. This emphasizes the importance of recent investments in universalizing early childhood education in Türkiye. It is suggested that further research be conducted in order to control SES and other demographic variables.