This study explores the relationship between transformational leadership and the effectiveness of Professional Learning Communities (PLCs) in public schools in Hanoi, focusing on the perspectives of female educators, including teachers and school managers. A quantitative, cross-sectional research design was applied, using stratified random sampling to collect data from 360 female participants (207 teachers, 141 vice-principals, and 12 principals) across primary, secondary, and high schools. Data were gathered through a structured questionnaire that assessed three dimensions of transformational leadership--Setting Direction (SD), Developing People (DP), and Restructuring the Organization (RO)--along with PLC effectiveness using the PLCA-R instrument. Reliability was confirmed through high Cronbach's Alpha coefficients (ranging from 0.717 to 0.949), and exploratory factor analysis (EFA) demonstrated the model's validity. The results from Pearson correlation analysis indicated strong positive relationships between all dimensions of transformational leadership and PLC effectiveness, with particularly significant correlations between leadership and Supportive Relationships (SCR), and Collective Learning and Application (CLA). The study found that transformational leadership had a strong influence on the "soft" elements of Professional Learning Communities (such as collaboration, collective learning, and shared vision), but had a negligible impact on the "hard" elements related to organizational structure, thereby emphasizing the central but limited role of leadership in developing a learning culture in public schools in Hanoi. These findings offer valuable insights into how transformational leadership can enhance PLC effectiveness in Vietnam's educational context, providing implications for leadership development and policymaking. However, the cross-sectional design limits causal inference, and the study's focus on Hanoi's public schools calls for future research in diverse educational settings across Vietnam. Longitudinal and qualitative studies would further deepen the understanding of the long-term impacts of transformational leadership on PLCs.