Do social cognition and epistemological understanding promote elementary school children’s experimentation skills? To investigate this question, 402 children (ages 8, 9, and 10) in 2nd, 3rd, and 4th grades were assessed for their experimentation skills, social cognition (advanced theory of mind [AToM]), epistemological understanding (understanding the nature of science), and general information-processing skills (inhibition, intelligence, and language abilities) in a whole-class testing procedure. A multiple indicators multiple causes model revealed a significant influence of social cognition (AToM) on epistemological understanding, and a McNemar test suggested that children’s development of AToM is an important precursor for the emergence of an advanced, mature epistemological understanding. Children’s epistemological understanding, in turn, predicted their experimentation skills. Importantly, this relation was independent of the common influences of general information processing. Significant relations between experimentation skills and inhibition, and between epistemological understanding, intelligence, and language abilities emerged, suggesting that general information processing contributes to the conceptual development that is involved in scientific thinking. The model of scientific thinking that was tested in this study (social cognition and epistemological understanding promote experimentation skills) fitted the data significantly better than 2 alternative models, which assumed nonspecific, equally strong relations between all constructs under investigation. Our results support the conclusion that social cognition plays a foundational role in the emergence of children’s epistemological understanding, which in turn is closely related to the development of experimentation skills. Our findings have significant implications for the teaching of scientific thinking in elementary school and they stress the importance of children’s epistemological understanding in scientific-thinking processes.