The aim of this study was to identify the barriers to knowledge sharing among teachers in Iran using a qualitative and phenomenological approach. Data collection was performed using semi-structured interviews, and data saturation was achieved after interviewing 11 teachers who were creative in teaching. All interviews were simultaneously recorded, transcribed, and analyzed using the seven-step Colaizzi's process. Findings revealed 49 conceptual codes that were categorized into three main concepts along with their sub-concepts. The cultural dimension involved four sub-concepts: including lack of belief in knowledge sharing of the effectiveness of knowledge sharing in education (5 conceptual codes), distrust (4 conceptual codes), lack of flexibility in the learning process (6 conceptual codes), and governance of a closed culture (6 conceptual codes). The communication dimension included sub-concepts of weakness in the underlying factors contributing to knowledge exchange (9 conceptual codes), IT problems (6 conceptual codes), ignorance of the existing media for knowledge exchange (4 conceptual codes), and inability to manage human resources (6 conceptual codes). Finally, Lack of supporting leadership included the sub-concepts of deficiencies in the annual evaluation form of teachers (4 conceptual codes) and mismanagement (6 conceptual codes).