This qualitative case study was designed to explore the role of early childhood education and early childhood special education personnel preparation programs in providing training in effective professional collaboration knowledge and skills to preservice early childhood professionals. Effective collaboration practices are important processes that contribute to the creation of successful inclusion programs. Preparing preservice educators to demonstrate effective collaboration skills is critical to promoting positive attitudes and initiating successful collaboration practices that support inclusion in preschools. The evidence was collected through different sources such as interviews with program faculty and undergraduate students, reviews of course documents, and observations of classes. The data provided in-depth information regarding the extent that the two programs prepare their pre-service teachers to develop effective collaboration skills. The experiences of the program faculty and students toward collaboration and teaming were positive and supportive in general. The program faculty and students identified several challenges in teaching and learning about professional collaboration and provided multiple recommendations to improve training of preservice teachers in professional collaboration practices. Furthermore, the findings of the study regarding the methods of training in collaboration and teaming indicated a need to increase applied collaboration skills through coursework, field experiences, and practica. Providing professional collaboration knowledge with limited opportunities to practice collaboration skills was insufficient to prepare preservice early childhood teachers to be effective collaborators with other professionals in inclusive preschools. In addition, the findings highlighted similarities and differences between the early childhood education program and the early childhood special education program regarding training in collaboration. The findings of this study led to recommendations for policy, personnel preparation practices, and future research in order to prepare early childhood professionals to collaborate with other education professionals to enhance the quality of inclusive programs in early childhood settings