In Lao People's Democratic Republic, two streams exist in pre-primary education, the standard three-year and a one-year preparatory class called 'Grade Zero system'. This research aims to investigate the introduction of the Grade 0 system, one-year pre-primary class, and its impact on ethnic minority children in rural villages of Lao PDR. The research methodology included qualitative research comprising interviews with villagers, school authorities, and an officer of the local education office and observations carried out at schools in rural villages. The results show Grade 0 has been introduced in accordance with the circumstances of attached primary schools; more specifically, small villages with incomplete schools offer Grade 0 because they can't possess three years pre-primary education. Moreover, Grade 0 plays an important role in the acquisition of Lao language when entering primary school. For instance, the repetition rate greatly improved due to the adequate preparation period. Grade 0 is an effective system in bridging the gap in primary schools, especially for minority children whose linguistic and cultural background is different from majority. As pre-primary education has finally been considered important, more international study projects will be essential, such as contemplating the construction of schools, teacher trainings, and bilingual education.