A growing body of evidence supports the importance of nurturing children's thinking. This article reports on an investigation of the influence of teachers' implementation of the Visible Thinking approach developed within the Harvard Graduate School of Education Project Zero on very young children's concepts of thinking, as measured by the drawing-telling technique. The researchers followed 146 three- to five-year-old children in the classrooms of 10 teachers over a period of 6 months to explore how the children's concepts about thinking developed. The current study first describes the theoretical framework that defines the cluster of concepts related to thinking about thinking (metacognition), social influences on children's concepts of thinking, and cognition and child development. The study is then described, with results showing that the children whose teachers were strong in implementing the Visible Thinking approach advanced their conceptions about thinking after being exposed to the Visible Thinking ideas. (Contains 3 tables.)