There has been longstanding concern about achievement differences across ethnic groups. Inattention is a significant factor associated with underachievement, and higher ratings of inattention have been found for some minority groups. The present study examined the relationship between inattention and achievement across Caucasian, African American, and Hispanic first graders. Thirty-three teachers rated over 600 students on their academic achievement, inattentive classroom behavior, oppositional behavior, hyperactivity, and anxiety. Only attention problems, and not other behavior problems, were independently associated with diminished academic achievement. Of particular interest is that a substantial portion of the achievement gap between African American and Caucasian students was related to higher rates of attention difficulties among the former, even though attention problems and achievement were more strongly associated among Caucasians. The implications of these findings for efforts to promote student achievement, and to reduce the achievement gap between African American and Caucasian students, are discussed.