There has been a significant increase in access to early childhood education for children from low-income backgrounds in Chile over the past two decades; however, there is little research that assesses the effects of these programs on improving these children's academic outcomes. Responding to this need, the present study assesses the impact of Chilean public early childhood education programs on the fourth-grade academic achievement scores of children primarily from low-income backgrounds. This study also estimates long-term effects of dosage, age of enrollment and program auspice on students' academic achievement. Results indicate that early childhood care and education (ECCE) is positively associated with academic gains on all three SIMCE tests: mathematics, reading, and social science, after controlling for children's socio-demographic factors associated with selection into ECCE. Children who attended public ECCE scored significantly higher on SIMCE tests than children who did not attend. Nonetheless, not all children benefit equally from attending ECCE. Findings from the present study suggest that boys benefit more than girls in terms of academic outcomes, and that the ECCE effect on academic achievement also differs depending on the children's SES. Middle-low SES children benefit the most, while children from low SES backgrounds do not seem to benefit significantly. The present study shows that the most important decision Chilean parents make regarding ECCE appears to be whether to enroll their children in a public ECCE program, and not at what age to enroll them, for how many years they attend, or the program auspice they choose. Findings are discussed in terms of their implications for research and policy.