Currently, school-based management (SBM) has become the most prominent feature of public school systems in most countries around the world. In Indonesia, a Commission of National Education recommended the establishment of school councils at the school level to improve the quality of national education. This study is aimed at examining whether improvements in student achievements have been achieved resulting from implementing SBM. The research was conducted in 2007 employing both quantitative and qualitative methodologies consisting of an empirical survey with active participation of 504 respondents who were school council members, and semi-structured interviews with 42 participants belonging to all categories of representatives of school councils as well as documentary analyses. The research was conducted at 42 primary schools in Ngada District in Flores. Data generated from the two phases of the research demonstrate SBM policies and programs have created better teaching and learning environments resulting in improved student achievements.