The study analyzes the concept of transnational learning in the context of professional development for teachers. The aim of the study is to theoretically reflect on transnational learning as a tool for the multi-dimensional professional development of teachers in the 21st century. One of the goals defined by UNESCO to be reached by the year 2030, is improved quality of education and lifelong learning, including teacher professional development. Teacher Professional Development Forms develop and change both vertically and horizontally, from passive to active solution search, experience-based learning. The study examines the professional growth of adults in 3 different theories: Kegan constructive-developmental theory, Drago- Seversone learning-oriented model for school leadership and Nonaka and Takeuchi SECI organizational knowledge creation theory. The authors' conclusions on transnational learning as a tool for teacher professional development are based on the findings of, Bruno-Jofre, and Johnston, as well as Johnson and OECD. As well as researching previous studies on transnational learning available on the Ebsco and Web of science websites. Methodology: In the process of research, using the method of analysis of scientific literature, conclusions have been drawn on the transnational learning role in the professional development of teachers.