The purpose of the study is to acquire knowledge and understanding of successful school development, with a focus on students' cognitive abilities. The survey focuses on the implementation of development work and its effects on the organization and students' development. The theoretical framework is based on special educational perspectives, salutogenic perspective and organizational theory. Two contiguous preschool class‑third grade schools are included in the study and primary data consists of interview responses from school staff. The study also includes questionnaire responses from guardians of children in third grade. However, the response rate from the guardians is insufficient for conclusions. The results show that school development changed the view of students' differences and needs. Furthermore, the schools have shifted their focus to group and organizational level, as well as to more promotional and preventive work. Fewer students are included in the student health team and the number of action plans has decreased. The development of the schools is characterized by a shift towards a more critical perspective and has been conducted through strengthened meaningfulness in the form of defined values, consensus in purpose and vision and collegial cooperation. The conditions that enable successful school development are characterized by a strong sense of coherence, in both leadership and conditions. Increased focus on the environment, as well as enhancement of comprehensibility, manageability and meaningfulness, are also factors that have benefited students' development. Factors that hinder school development can be traced to a compensatory and dilemma perspective, as well as to a lack of sense of coherence. Above all concerning attitudes among school staff and external demands placed on the school activities. Our conclusion is that both school development and students' cognitive abilities can be promoted through the application of a salutogenic perspective.