The key response of educational system to the challenges of the XXIst century related to the dynamics of the labor market, digitalization and the need to form flexible competencies is transformation of educational organizations into self-learning ones, which are capable of reflection, adaptation and continuous development. The practical mechanism of such transformation is formative assessment, which is a continuous process of diagnosis and correction of learning activities as opposed to the ascertaining function of summative assessment. Its system-forming role is revealed through a set of didactic principles: a focus on designing «growth points» instead of stating results, timely feedback, its concreteness and operationalizability, as well as dialogism as a basis for a joint analysis of the educational process. The integration of formative assessment has a structuring effect on three basic elements of a self-learning organization: it stimulates an individual professional development of a teacher through reflection based on empirical data; it serves as a catalyst for meaningful teamwork of the teaching staff and institutionalizes the focus on improvement, putting management on an evidence-based basis. The implementation of this approach requires a consistent strategy, including the creation of a psychologically safe environment that legitimizes an error as a learning resource, the purposeful introduction of tools and a reflection phase to adjust practices. The final result of the introduction of formative assessment is a profound transformation of the educational model. This approach implements the cyclical nature of organizational development into everyday school practice, turning each feedback act into an educational resource. This shift contributes to the evolution of the school from a closed hierarchical structure to a flexible educational ecosystem, where a collective entity is formed, endowed with the ability to critically reflect on the present and design the desired future. This process marks the formation of an educational organization that constantly carries out self-renewal and self-improvement through understanding its own experience.