Research Findings: The purpose of this study was to examine the frequency of extratextual references to letters made by parents and preschoolers during shared reading of an alphabet book. The frequency of letter references was also examined in relation to child age and knowledge of letter names. Participants consisted of 44 preschoolers and their primary caregivers. Videotaped book-reading data were transcribed verbatim and coded for their inclusion of 14 types of letter references (e.g., naming requests, labels, repetitions). Significant findings included the following: Parent labels were significantly correlated with child age; and child knowledge of letter names was significantly correlated with parent naming requests, corrections, and repetitions, and child answers and initiations. Practice or Policy: Findings are discussed in reference to the literature regarding parental sensitivity to child age and knowledge in educational interactions with their child. (Contains 3 tables.)