This study aimed to determine the relationship between school culture (SC), professional learning communities (PLCs), and school effectiveness (SE) in the correlational research model through structural equation modeling. The sample of the study consisted of a total of 358 teachers working at public schools in various provinces of Turkey. Thus, data from a total of 355 teachers were analyzed. In the analysis of the data, the mediator and direct role of the variables were examined through path analysis. Finally, the fourth study hypothesis examined the relationship between these three variables and teacher characteristics. In general, the study results revealed that a supportive, achievement-oriented, and task-oriented SC was important for SE and the exhibiting of PLCs behaviors. In this context, it can be argued that paying attention to these cultural components and applications, which turn teachers into PLCs, is of significance in making schools effective. Teachers' perceptions of the PLCs, SC, and SE in a centrally managed educational system, and the relationships between these variables can contribute to school improvement.