ABSTRACT This article investigates the significant disparities that often occur between mathematics teachers’ written reflections of their class from memory and their reflections after later observing a video of the same class. Data was collected from journal and video documentation made during in an M.Ed. course about post-lesson analysis. The disparities were examined based on the theoretical literature with the participation of the teachers, who shared their interpretations as to the reasons for them. The three educational and cognitive theories that formed the basis for the discussion were Tulving’s theory regarding episodic (personal experience) and semantic (general knowledge) memory; Mason’s theory about noticing and awareness; and Wimber et al.‘s theory about memory mechanisms that can lead to forgetting specific memories or by which remembering specific events can lead to forgetting others. As a result of the analysis, three disparity types were defined: “memory extinction”, “misguided interpretation”, and “false memory”, indicating that selective memory and forgetfulness may be at play when teachers write their reflections. The results of the study led to suggesting a five-stage reflective analysis method to enhance teachers’ noticing focus and abilities. They also emphasize the importance of group discussions on theories related to ‘reflection’, ‘noticing’, and ‘memory’ to improve teachers’ interpretation of teaching events.