Developmental psychologist John Flavell (1979, 1981) used the term metacognition to encompass any form of thinking about one’s thinking. Flavell did not consider this second-level capacity to be a regular part of the thinking and learning of preschool children. However, research using developmentally-appropriate tasks, especially early literacy tasks, has suggested otherwise. Therefore, through this qualitative and exploratory study, I investigated whether and how seven 4-year-olds attending full-day preschool were metacognitive as they read narrative picture books with me in their classroom. Over the course of their pre-kindergarten school year, during free choice morning centers, I engaged the participants in three joint readings of commercially available, narrative picture books. Throughout the informal dialogue of each joint reading session, I posed questions meant to encourage metacognitive processing. I transcribed the dialogue from these sessions and coded each researcher and participant speech turn. I then utilized a constant-comparative process to analyze transcriptions throughout the data collection process while referring to Flavell’s (1979, 1981) conceptualization of metacognition and prior studies of metacognition with preschool participants. This process resulted in the articulation of seven categories of metacognition relevant to preschoolers’ joint reading processes: Feeling of Knowing Story Content, Judgment of Difficulty, Reflecting on Reading, Verbal Self-Revising, Expanding Storytelling, Task Planning, and Justifying Verbalizations. Participants engaged in a total of 219 instances of these forms of metacognition. Approximately 60% of these instances were prompted—occurring in response to a question that I posed within the joint reading dialogue. However, approximately 40% of recorded instances of metacognition occurred spontaneously. All seven participants were metacognitive in at least five of the seven categories, across all four books, and through both prompted and spontaneous verbalizations. Consistent with Flavell’s (1979) conceptualization, metacognition functioned as a transactionally-relevant resource for each joint reading participant, manifesting in ways that reflected varying efforts to participate in the task and construct meaning from the story. My results challenge the notion that metacognition has limited relevance before proficient or conventional print reading (Baker, 2005; Hacker, 1998; Pressley & Gaskins, 2006; Veenman, et al., 2006) and provide further support for Whitebread et al.’s (2009) conclusion that underappreciation of the metacognitive capabilities of preschoolers is becoming an “increasingly untenable” position (p. 64). Given my findings, I discuss implications for metacognitive theory and for future research on reading-relevant metacognition with preschool children.