The two goals of this study are to examine the impact of an early childhood teacher’s metacognition-driven, place-based science teaching professional development (PD) intervention and to explore the association between science teaching and environment quality and children’s self-regulated learning. A total of 110 children (Mage = 60 months) and 20 teachers from preschools and kindergartens in rural regions of Idaho, U.S., participated in this mixed-methods study between August 2022 and May 2023. Children’s and teachers’ pre-test and post-test data were collected using validated observation tools, surveys, and reflection journals. The results from repeated measures ANOVA and linear mixed regression show that there were statistically significant increases in children’s self-regulated learning scores and teachers’ science teaching efficacy and metacognitive knowledge, but not metacognitive regulation skill scores post-PD. Thematic analysis revealed evidence about children’s learning interests and inquiry skills, and that science activities supported children’s learning in other subjects and developmental domains (e.g., literacy, mathematics, and social-emotional skills). Our results indicate the potential for supporting young children’s self-regulated learning by training teachers to implement a developmentally appropriate, hands-on science curriculum that focuses on reflective thinking and a holistic understanding of science concepts and process skills.