Research Findings: Environmental print provides children with their earliest print experiences. This observational study investigated the frequency of mother-child environmental print referencing and its relationship with emergent literacy. A total of 35 mothers and their children (ages 3-4 years) were videotaped interacting in an environmental print-rich play setting. The frequency of environmental print referencing of letters and words was measured. Children were assessed on emergent literacy skills (letter name and sound knowledge, print concepts, phonological awareness, name and letter writing, environmental print reading). In all, 69% of mothers referenced environmental print. After child age, home literacy teaching, and maternal education were controlled for, greater maternal referencing of environmental print was positively related to print concepts and name and letter writing. Child environmental print referencing was positively related to name and letter writing as well as to maternal environmental print referencing. Mothers used a range of mediation strategies to support children's interactions with environmental print. Practice or Policy: Maternal referencing of environmental print may be a useful way to scaffold emergent literacy in young children.