The study explores the impact of a Gender-Responsive Play-Based Learning (GR-PBL) training package for pre-primary teachers in Rwanda and Mozambique. Utilizing mixed methods, including the IDELA toolkit for assessments, the research found contrasting outcomes in the two countries. In Mozambique, the training significantly improved classroom environments and child learning outcomes, especially in emergent literacy, attributed to better teaching experience. In Rwanda, however, challenges such as overcrowded classrooms, lack of resources, and insufficient support from school leaders hindered similar improvements. Teachers in both countries showed positive shifts in attitudes towards integrating play-based pedagogies and gender responsiveness in their classrooms. The study emphasizes the need for context-specific teacher training programs, continuous support for educators, and better learning conditions to ensure effective implementation and scaling of such pedagogical approaches in Early Childhood Education.