A number of studies provide evidence that the home numeracy environment is important for the development of early numeracy skills. There is also evidence that preschoolers understanding of math language is a strong predictor of numeracy skills. However, there is limited research on the role of math language knowledge in the relation between the home numeracy environment and early numeracy skills. The purpose of this study was to investigate the relation between the home numeracy environment (engagement in direct numeracy activities) and numeracy skills while considering math language as a mediator. Participants included 125 children between 3.12–5.26 years (M = 4.17, SD = 0.58) and their parents. Parents reported on the frequency of engaging children in direct numeracy activities. Children were assessed in the fall and spring of their preschool year on their numeracy skills and math language knowledge. Results suggest that math language mediates the relation between the direct home numeracy environment and numeracy skills. These findings provide evidence that the relation between the direct home numeracy environment and early numeracy may be explained by preschooler’s math language knowledge. (Author abstract)