This study investigated the accuracy of classroom teachers' judgments of the reading progress of their low-performing students. Participants were 36 second grade teachers and students in their lowest reading groups (n = 150). Student progress was monitored weekly using reading-curriculum-based measurement (R-CBM) procedures. After 6 weeks, teachers were asked to rate their students' progress. Expert judges later reviewed the teachers' R-CBM graphs and rated the individual and group progress based on the graphs. Teacher ratings did not correlate with expert ratings or the R-CBM slope estimates. Expert ratings correlated highly with slope estimates. Teachers' estimates of progress were significantly higher than expert judges' ratings, indicating that teachers may overestimate student progress. Implications for practice and future research are discussed. © 2008 Wiley Periodicals, Inc.