Georgia has been at the forefront of the pre-kindergarten movement since implementing its pre-k program in 1992 and creating the nation's first state-funded universal pre-k program in 1995. Georgia's Pre-K, administered by "Bright from the Start: Georgia Department of Early Care and Learning" (DECAL), aims to provide high-quality preschool experiences to four-year-olds to help prepare them for kindergarten. This study evaluated the impact of two professional development models--Making the Most of Classroom Interactions and MyTeachingPartner™--on teacher-child interactions in Georgia's Pre-K classrooms. At the start of each school year of this three-year study (2011-12, 2012-13, 2013-14), lead teachers (n = 486 over the entire project) were randomly selected to participate and randomly assigned to one of the professional development models or a control group. The two professional development models evaluated in this study are designed to improve teacher-child interactions as measured by the Classroom Assessment Scoring System™ (CLASS). The CLASS focuses on three domains of teacher-child interaction: Emotional Support, Classroom Organization, and Instructional Support. The supports for both models were delivered by Georgia's Pre-K consultants, as part of their regular job duties. A technical appendix that provides more details about the research methods and analyses is also available at ED558590.