This study analyzed and compared the characteristics of expert and less expert teachers' noticing ability during observation of literacy instruction, and builds a conceptual framework for expert noticing during such teaching. Expert participants (n = 7) were defined as university faculty in reading with intensive and long-term experience in clinical settings. Less expert participants were students in a university graduate program in reading (n = 22) with at least three years of classroom teaching experience. Data sources were participants' transcribed audio-recorded observations made while observing literacy lessons. Analysis involved open coding processes including line-by-line coding of transcripts, identification of emerging themes, and summarization of the noticing content of each transcript. Researchers identified pivotal events within each literacy lesson and examined transcripts for observer comments matched to these events. The study confirmed applicability of research on expert noticing in other contexts to literacy instruction, and identified important differences in noticing between experts and novices. Characteristics that distinguished expert from less expert noticing included detailed hypothesizing, breadth and depth of elaboration, and the ability to see a learner's metacognitive behaviors as well as pivotal events during instruction. These attributes of expert noticing appear to be highly consequential for effective instructional decision-making, and explicit activities targeting the advancement of teachers' noticing skill are recommended for teacher professional development. (Contains 5 tables and 2 figures.)