This study examined whether maternal evaluations of children's emergent literacy (EL) levels, maternal mediation during a book-reading activity with children, and the children's EL levels differ as a function of socioeconomic status (SES; low vs. high), and whether the relationships between these variables differ as a function of SES levels. Study participants included 84 kindergarteners, 41 from low SES (LSES) and 43 from high (HSES) families, and their mothers. Maternal evaluations of their children's EL levels were gathered, mother-child interactions in a book-reading activity were videotaped, and the children's EL levels were independently assessed. LSES mothers were less accurate in evaluating their children's EL levels and exhibited lower mediation levels in the book-reading interactions. Their children exhibited lower EL levels than did the children in the HSES group. In the HSES group, children's EL levels were explained by maternal evaluations and by maternal mediation levels. HSES maternal mediation levels while book reading were explained by their children's EL levels. No such relationships appeared between these variables in the LSES group. Suggestions for educational practices and further research are discussed.