Previous research shows that Early Childhood Education (ECE) positively impacts cognitive outcomes later in life. Few studies examine the impacts of ECE in developing countries. We use data from the Young Lives project in Vietnam with 2SLS regressions to estimate the impact of years spent in ECE on cognitive outcomes in adolescence. We find that one year in ECE corresponds to 21.8 percentage point (1.25 SD) and 30.8 percentage point (2.78 SD) increases in math and verbal cognition scores, respectively. Our estimates suggest that ECE is highly effective in Vietnam and is a potential strategy for bridging educational outcomes gaps.