Today's modern society is facing numerous challenges and changes which inevitably lead to changes in the context of education. Such rapid changes in the developmental processes of society require teachers to embrace lifelong learning and continuously work on their selfimprovement in order to keep up with these changes and cope with them successfully. Therefore, in response to the set imperatives of the educational process, the implementation and realization of teacher professional growth is imposed. Contemporary educational tendencies in the world are directed towards regular investments in professional growth, which seeks to affirm teacher self-improvement with the continuity of constant enrichment of knowledge and increasing expertise. The Interconnected model developed by Clarke and Hollingsworth (2002) is an example of teacher professional growth that takes place through four intertwined domains of teacher action. The aim of this research paper is to examine how this model works in the Croatian education system on the examples of biology teachers. The theoretical part of this paper gives an overview of the theoretical foundations and different approaches to considering and understanding the issue of teacher professional growth. The application of the model in numerous studies relating to the teacher professional growth was especially elaborate on. The empirical part of the paper presents the results of research obtained by forming four topics, named according to the domains from the Interconnected model of teacher professional growth: external domain, domain of consequence, personal domain and domain of practice. The results showed the complexity of teacher growth network processes that sometimes take place simultaneously in different domains and in different directions. It was found that the process of teacher change is not a linear process, but that the nonlinear structure of the model allows for multiple changes while respecting the individuality of teacher’s professional growth. The study confirms the importance of continuous investment of teachers in their own professional growth, but also the need for teachers to improve in specific and tailored topics. In this context, it is important to emphasize that the high motivation of teachers, openness to change and voluntary participation in various professional growth activities are important factors of their personal and professional progress. Although the research is limited to six case studies, it indicates that teacher changes are achievable with appropriate support, but also that they depend on each individual. The paper contributes to the deepening of scientific knowledge in the field of teacher professional growth, which is an important strategy in achieving the general well-being of students and schools, and thus the education system as a whole.