This study explores and compares the role of Bangladesh's universal preschool in enhancing learning achievement at the end of primary education before and after introducing a new policy. Children's access to preschool has increased, and the learning achievement of the preschool non-participants' decreased after introducing the new policy. The capability of the state-run provision, which creates the preschool opportunity for the majority of children, has increased with a small effect size. The private kindergartens continued to show better performance with no change over time. The challenges include creating opportunities for out-of-preschool children and quality improvement of some existing provisions.