Science, technology, engineering, and mathematics (STEM) in early childhood education is an area currently given little attention in the literature, which is unfortunate since young children are natural scientists and engineers. Here, we outline our mixed-methods design-based research investigation of a pre-kindergarten (Pre-K) classroom where two early childhood educators are incorporating STEM activities. We used a protocol consisting of a list of potential characteristics of effective and appropriate STEM curriculum for young children to structure our classroom observations. We also used semi-structured interviews, focus groups, and a questionnaire to collect data from multiple stakeholders (teachers, students, and parents), to examine how STEM activities were incorporated in Pre-K, to explore students' engagement with STEM concepts, and to investigate parents' opinions about STEM in general and STEM as experienced by their children. Our findings provide support for the inclusion of STEM-based learning experiences for young children.