Science, technology, engineering, and mathematics (STEM) have been a major focus for education reforms over the last decade, including how to support underrepresented minorities' entry into and retention in STEM fields. Using Bronfenbrenner's ecological systems theory as a framework, the current study explored the systematic barriers Black children and children of other marginalized racial groups face in STEM success. STEM learning begins at birth, but most research looking at STEM education begins in kindergarten and beyond. In this article, we review what we know about STEM in early childhood from the microsystem influences of family and school resources to the macrosystem of the educational barriers within broader society. Early childhood educators report being underprepared to support STEM learning and unable to identify STEM learning opportunities for very young children (McClure et al., 2017). An underprepared workforce, as well as a lack of access to high-quality preschool programs, likely contribute to the achievement gap between Black children and White children on math performance at kindergarten entry (Nores & Barnett, 2014). We end our article with a call to action, outlining what we think researchers, policy makers, teachers, and communities need to do to better support young children of color and their STEM learning.What is the significance of this article for the general public?To meet the needs of today's society, there is a growing demand for diversity in STEM fields. By supporting children of color, specifically Black and Brown children, and their early introductions to STEM, we can foster a learning environment where all children, regardless of race, socioeconomic status, and ability, can develop a passion for and pursue a STEM education.