The purpose of this study was to examine the extent to which teacher ratings of behavioral attention predicted responsiveness to word reading instruction in first-grade and third-grade reading comprehension performance. Participants were 110 first-grade students identified as at risk for reading difficulties who received 20 weeks of intensive reading intervention in combination with classroom reading instruction. Path analysis indicated that teacher ratings of student attention significantly predicted students' word reading growth in first grade even when they were competed against other relevant predictors (phonological awareness, nonword reading, sight word efficiency, vocabulary, listening comprehension, hyperactivity, nonverbal reasoning, and short-term memory). Also, student attention demonstrated a significant indirect effect on third-grade reading comprehension via word reading but not via listening comprehension. Results suggest that student attention (indexed by teacher ratings) is an important predictor of at-risk readers' responsiveness to reading instruction in first grade and that first-grade reading growth mediates the relationship between students' attention and their future level of reading comprehension. The importance of considering ways to manage and improve behavioral attention when implementing reading instruction is discussed.