This study aims to explore participation in the Effective Classroom Interactions for Toddler Educators (ECI-TE) course and if doing so was associated with changes in their noticing and implementing effective educator-child interactions. Sixty-one center-based toddler educators were randomly assigned to control or participation in ECI-TE, an online content and coaching professional development course. Findings showed that participants who engaged in the course were highly satisfied with ECI-TE and found the experience helpful. Both groups showed low noticing skills and quality of educator-child interactions; however, participants in the treatment condition showed greater noticing skills and higher quality of educator-child interactions with a medium effect size. Nonetheless, educators’ participation in the course raises concern about the workforce stability. Specifically, during the course, many educators either left the field or had difficulty engaging due to competing demands, limiting the stability in the field and potential to transform early care quality at scale. Results have implications for how we consider and support the professional development needs of toddler educators to foster children's positive development and future school readiness. (author abstract)