Teachers and administrators are faced with a basic question when planning for a school year: how should the students be grouped when coming to school? Should students of similar age be together or should students be assigned to multi-age classrooms at the elementary school level? If the multi-age method is chosen, how will academic progress be affected by this instructional strategy? And, in the end, will the students in a multi-age setting perform similar to students who are in traditional group setting on standardized tests? The question of multi-age grouping and academic performance was the focus of this study. The purpose of this study was to compare the academic performance in reading and mathematics of third- and fifth-grade students who have completed three years of multi-age instruction with the academic performance of students in third and fifth grade who have been instructed in the similar-aged traditional classroom. The study compared test scores of students in third and fifth grades using the Minnesota Comprehensive Assessment exams. This study determined that there was no significant difference in the scholastic performance between the groups of students who were instructed in the multi-age instructional settings compared to the traditional same age setting. The multi-age setting does allow for positive social settings particularly the opportunity for students to take leadership roles with fellow classmates. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]