The purpose of this research is to identify factors that influence the functioning of a school working as a Professional Learning Community (PLC) and to analyze the links between these factors and the school's progression. This research was developed within the context of an interpretative research paradigm. The primary data collection tool employed is a one-hour semistructured interview with each participant, thus allowing researchers to identify each participating school's level of development as a PLC and clarify the underlying factors that have a positive effect on this type of functioning. The interview plan, composed of themes relevant to this research project, is structured according to the Seidman model (1998). The schools were classified according to the three stages of development identified in the Professional Learning Communities Observation Grid (PLCOG) from Leclerc, Moreau and Lepine (2009a), namely the initiation, implementation, and integration stages, using the seven indicators found in the professional literature. This study suggests certain dominant factors, particularly for schools in the initiation and integration stages. Recommendations are presented to better assist school administrators in supporting their teaching staff as a PLC. (Contains 4 tables and 2 figures.)