The main purpose of this study is to analyze the effects of factors affecting the level of elementary schools’ in-school professional learning community in a multi-layered way. In order to achieve the purpose, teacher related variables and school related variables were divided and searched for predicting variables that affect professional learning communities. The results of the search showed that the teacher related variables were composed of 11 variables and school related variables were composed of 7 variables. A total of 18 variables were selected as final variables affecting the level of elementary schools’ in-school professional learning community. The main results are as follows. First, about 78.8% of the level of elementary schools’ in-school professional learning community was explained by school related variables. Second, educational level and positive feedback of teacher related variables, and principals leadership, participating decision making, teacher cooperation of school related variables had influence on the level of elementary schools’ in-school professional learning community. Third, in order to improve the quality of elementary schools’ in-school professional learning communities, the Ministry of Education, the City Office of Education, the Regional Education Support Office, principals should do policy approach focusing on school management process variables.