The goal of this brief is to describe the implementation of the We Grow Together (WGT) Professional Development System during a field test conducted in late fall 2018 to spring 2019. WGT is a research-based PD system for caregivers working with infants and toddlers in center-based care and FCCs. As part of WGT, caregivers work with their PD providers using resources delivered through a website. The system supports caregivers in planning and using the WGT practices through relationship- and practice-based coaching. A field test of WGT examined implementation with teachers and caregivers of infants and toddlers and their PD providers in Early Head Start, FCCs, and community-based child care settings. (author abstract)