Mentors' perceptions of factors associated with educational change were identified following an individualized mentoring program about constructivist curriculum for early childhood educators. A qualitative case study analysis of the mentors' journals of six classrooms was conducted to review their perceptions of change. Classroom environment quality was assessed with the Early Childhood Environmental Rating Scale-Revised (ECERS-R) before and after the intervention program. At post-intervention, mentors reported that classrooms with increased ECERS-R Activities scores were likely to engage in behaviors promoting change, for example reflective skills, documenting children's learning, and challenging their own beliefs. In contrast, educators in classrooms with relatively stable post-intervention ECERS-R Activities scores appeared to create barriers that inhibited change. For example, they were less willing to challenge their beliefs, make changes in practice, and to document children's learning. Recommendations presented in the paper focus on successful implementation of mentoring programs; policy implications indicate that individualized mentoring programs require proper financial and personnel supports.