Previous studies have identified many school variables which can have significant effect on academic optimism. However, most of these identified variables are leadership or psychological constructs; thus, it is often too abstract for school administrators to translate into real practice. Therefore, this study adopted the perspective of school resources and investments to examine to what extent is academic optimism determined by school preexisting conditions, and what school investments can promote it. The data were collected from a sample of 3672 teachers from 326 junior high schools in Taiwan. A hierarchical regression analysis was used to address research questions. The results indicated that school resource, the preexisting conditions of a school, only has marginal effect on academic optimism. It is school investment that has the majority of the impact on academic optimism. The study further identified that the school investment in Internet connection, awards for student learning, parent education, teacher professional development and its incentives can have significant effect on academic optimism. The paper contributes to better understanding of the nature of academic optimism and indicates what school investments educational practitioner can focus on to foster the culture of academic optimism.