The purposes of this study were to investigate the following: (a) the impact of sex, ethnicity, socioeconomic status, and family income on the likelihood of whole-grade skipping between kindergarten and Grade 7 and (b) the effects of grade skipping during elementary or middle school on students' academic achievement in high school. The authors used the second follow-up data set from the National Education Longitudinal Study of 1988 (NELS:88) to identify 238 students who skipped one grade between kindergarten and Grade 7. They found that females, Whites, and high socioeconomic status students were more likely to skip early. In addition, accelerants skipping kindergarten were more likely to excel in reading and mathematics at the 12th-grade level than those skipping later in elementary and middle school. (Contains 2 figures and 6 tables.)