The article deals with the issue of organising developmental educational environment at biology lessons.The study emphasises that modern education requires the introduction of new approaches that will help to form competences, develop critical thinking, abilities, creativity and independence of students. The purpose of the article is to substantiate the components, key principles and practical approaches to the organisation of developmental educational environment at biology lessons. Based on the analysis of modern researches, the article describes modern approaches to the definition of the concepts of «educational environment», «learning environment», «developmental educational environment». The authors have found that the educational environment is a multimodal space that should be in line with modern technologies, methods, and forms of learning.The components of the developmental educational environment are substantiated: target, value, technological, psychological, informational, subject-spatial and socio-cultural. The article presents practical approaches (developmental, competence and activity-based) and key principles for creating developmental educational environment at biology lessons (activity in learning, humanisation, problematic, relevant and timely knowledge, conscious participation of students in the educational process, freedom of choice of learning conditions). The authors note that developmental educational environment is a set of pedagogical conditions that contribute not only to the acquisition of knowledge but also to the development of skills and competencies, and create opportunities for students’ self-realisation. The authors of the article conclude that for the successful organization of the educational environment it is necessary to take into account its multifacedness, systematicity, complexity, as well as the need to improve technologies, methods and approaches for the purpose of the development of each individual. Key words: educational environment, developmental learning, developmental educational environment, didactic principles, practical approaches, biology lesson, education.