Early introduction to science and math encourages interest and learning in these subjects later in life. As children's first teachers, parents can expose their children to informal science and math learning activities before they enter formal schooling. It is important to understand how parents engage in science and math activities with their young children and whether parents' perceptions of their own science and math abilities affect their engagement with their child's informal learning, including using media as a learning tool. Using exploratory sequential mixed methods, we interviewed 12 parents and surveyed 187 parents to explore this issue. Our findings identify the science and math activities parents engage their preschool-aged children in and show that parental perceived efficacy in supporting their child's early science and math learning is related to the number of related informal activities their children do. Importantly, we found that perceived efficacy in supporting early science was related to science media use, but perceived efficacy in supporting early math was not related to math media use. This research broadens the understanding of how parents engage their child in science and math learning and can provide insight into how to empower parents to feel confident when they engage their children in science learning.