The practice of delaying students' entrance into kindergarten raises several questions. This literature review asks: (1) How does the entrance age of kindergarten children affect academic achievement?; (2) Do age-eligible older students perform better academically than younger students?; (3) Do year-older or "red-shirted" students have an academic advantage over younger students?; and (4) Do transitional programs such as pre-kindergarten and pre-first or junior first grade promote achievement for immature, high-risk students? After defining relevant terms, the review explores the history of entrance age issues; describes the major issues, controversies, programs, and contributors; and provides a synthesis and analysis. The review concludes that despite often contradictory research findings, school age does not affect academic achievement. The review recommends that more efforts be made to design kindergarten classes that are developmentally appropriate for all enrolled students. Contains 24 references. (EV)