Early childhood teachers play an important role in preparing young children for all later learning and development. Their teaching practices give children an understanding of what school is and how it works as they facilitate the construction of foundational knowledge. Teachers’ beliefs about their work impact their practices. This convergent, mixed-methods study explored the beliefs early childhood teachers hold, how those beliefs form, and connections between those beliefs and their daily teaching practices. Participants in this study described building their beliefs about their work through experience, interactions with others, and informal and formal study, with experience and interactions with others as the key factors in their belief development. Teachers build their own professional development networks that they use to develop their beliefs about teaching and related teaching practices. The implications of these findings are that early childhood programs and systems should work to facilitate peer-to-peer collaborative networks to help teachers develop their beliefs and related effective teaching practices.