Early acceleration is an educational practice to instruct students with advanced learning materials that are reserved for students at higher grade levels. One popular form of early acceleration is to provide students with early access to formal (abstract) algebra at the beginning of middle school. The present study aimed to determine how much growth in achievement accelerated students can demonstrate in each of four mathematical areas (basic skills, algebra, geometry, and quantitative literacy) in relation to their initial mathematics achievement at the beginning of middle school and examine whether accelerated students who have a faster rate of growth in achievement in one mathematical area also have a faster rate of growth in achievement in other mathematical areas. Furthermore, the present study aimed to examine the impacts of student and school characteristics on growth in each of the four mathematical areas and stability of growth across the four mathematical areas among accelerated students compared with non- accelerated students.The Longitudinal Study of American Youth (LSAY) is a six-year panel study of mathematics (and science) education of public middle and high school students (Grades 7 to 12) in the United States. A multivariate multilevel model was developed to account for correlation in achievement among the four mathematical areas and hierarchy in educational data (students nested within schools as in the case of the LSAY).Application of multivariate multilevel analyses to the LSAY data (N = 3116) showed that early acceleration of students into formal algebra promoted advantageous growth in all four mathematical areas regardless of students' mathematics achievement at the beginning of middle school. Low achieving (at the beginning of middle school) students particularly benefited from early acceleration into formal algebra. Low achieving students who were accelerated into formal algebra at the beginning of middle school grew not only faster than low achieving students who were not accelerated into formal algebra but also faster than high achieving students who were not accelerated into formal algebra. As a matter of fact, the rates of growth of accelerated low achieving students were even comparable to those of accelerated high achieving students. In addition, all low achieving students showed the same potential to take advantage of early acceleration regardless of their individual characteristics (gender, age, race-ethnicity), family characteristics (socioeconomic status, number of parents, number of siblings, and language spoken at home), and school characteristics (school size, school location, school socioeconomic composition, school racial-ethnic composition, academic expectation, disciplinary climate, parental involvement, principal leadership, teacher autonomy, teacher commitment, and staff cooperation). Overall, early acceleration of low achieving students into formal algebra at the beginning of middle school appeared to be a more successful case than early acceleration of high achieving students.Early acceleration of students into formal algebra at the beginning of middle school also promoted stability of growth across the four mathematical areas. Specifically, early acceleration was found to be related with consistent changes in rank in rates of growth across mathematical areas among accelerated students. Finally, this stability (or consistency) of growth across the four mathematical areas among accelerated students was not dependent on student and school characteristics.