The field of special education has made great strides in identifying interventions that work. These practices have been described as evidence-based because they were effective across numerous studies. However, scholars in the field are also acutely aware that not all evidence-based practices will be equally effective for all children. Because of this, we sought to gain a better understanding of just who participated in single-case research design studies published in two early childhood journals from 2011 through 2020. Demographics for 267 participants from 67 studies were coded and statistically compared with federal data. Results suggest an overrepresentation of male participants, an overrepresentation of Black children, an overrepresentation of children diagnosed with autism, and an underrepresentation of Hispanic/Latinx children.