Abstract
This study explores the use of a diary as a tool to mediate the strategic reading instruction of classroom teachers. The research is based on cultural‐historical activity theory and argues that human beings use tools to mediate their behavior. During weekly seminars, twelve teachers discussed the current literature related to research‐based reading instruction strategies. In the next phase of the study, researchers modeled how the knowledge from the literature on reading instruction could be used in instructional decision making with a basal reading program and regularly observed the teachers in their classrooms. Teachers used a diary as a tool for thinking about, planning, and implementing reading instruction. Analysis of data revealed that a diary may be an important media‐tional tool in helping teachers to access knowledge acquired during in‐service education and regulating their instructional activity.